How to paint and coat roofs

Q. The previous owner has painted the glass roof of our conservatory. The paint is peeling off easily. Is there a painting system I can apply to successfully reduce heat and brightness on glass?

A. It is likely no sealer applied to the glass first and that the paint has been directly applied to the glass, which is causing the problem.

Our recommended system is: Remove the entire existing coating. Thoroughly clean the glass surface. Apply a thin coat of Resene Waterborne Sureseal sealer and allow it to cure without water contact for at least 48 hours before overcoating. The sealer is not designed to be applied as a thick wet film thickness, the thinner the coat the better. Then apply two coats of Resene SpaceCote Low Sheen (if on the interior side of the glass) or Resene Lumbersider Low Sheen (if on the exterior side).

The new paint system will take five days to develop good initial adhesion and continue to cure for an additional three weeks until a full cure occurs. In the early stages, the paint surface will not have good resistance to cleaners or abrasion, as these features develop as the film undergoes curing.

Note that the painting will not reproduce the original features or hardness properties of the original glass and adding any paint system will always require a level of maintenance.

Resene Waterborne Sureseal is a coloured sealer and will not dry clear, if you plan to paint the exterior of the glass.

I would stick to light or white coloured topcoats to help with heat build-up.

November 2023

Q. I'm interested in the CoolColour technology. I have a torched on roof (black) which gets very hot, what can you suggest I paint it with? I have used Resene X-200 on the exterior walls. I liked the idea of an elastomeric paint.

A. Before heading down the painting avenue, check with the supplier/installer of the roofing membrane to see if changing the colour will affect the warranty. I have had a look at Vikings torch on membrane warranty and if the colour or aesthetics change, the warranty is void.

If you were still to proceed, after the area is thorough washed down, do a test patch using Resene Galvo-Prime followed by Resene Summit Roof semi-gloss in your chosen colour - CoolColour is recommended for darker colours.

November 2023

Q. I want to paint an existing corrugated iron roof (not COLORSTEEL®), which is showing signs of some flaking. What paint should I use?

A. Treat areas of moss/mould infestation with Resene Moss & Mould Killer diluted. For heavy infestations more applications may be needed. Scrub down using Resene Heavy Duty Paint Prep and Oil Remover. Rinse clean or hose down with copious amounts of fresh water ensuring all wash solution and surface chalk residues are removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, to leave only soundly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Spot prime prepared areas of corrosion with a coat of Resene Pre-Coated Steel Primer followed by a full coat of the primer and then finish with two coats of Resene Summit Roof in your topcoat colour.

We would recommend using the Resene CoolColour version of your colour, if you choose a darker colour, to increase the heat reflection of the colour. The CoolColour version of a colour has greater near infra-red reflection and does not retain as much heat compared to the same colour made using no cool pigments.

November 2023

Q. Our roof is old, galvanised iron with very faded red paint. We are going to paint with Resene Summit Roof CoolColour Grey Friars.

We want to maximise the CoolColour effect. We are unsure of what primer to use as two different painters have said Resene Galvo One and another Resene Quick Dry. We have already spot primed with Resene ArmourX GP Metal Primer.

Some of our roof is showing areas of near to no paint.

A. As long as the existing coating is sound I recommend you use Resene Pre-Coated Steel Primer (can be used over Resene ArmourX GP Metal Primer) followed by Resene Summit Roof semi-gloss. This will work in the CoolColour system.

November 2023

Q. I am looking to colour match the LT7 sheeting (a Dimond Roofing Product) to New Denim Blue. I have contacted Dimond Roofing and they have pointed me in your direction. I have looked at your range of light industrial coatings but would like to ask what your recommendations are for the best product available for this work. As the old sheeting is still in good order, my plan is to 3K water wash the sheeting clean. An abrasive scour pad will be used to slightly roughen up the surface. I would then look to apply an etching primer and then a topcoat.

I will also be needing an acrylic painting system for application on to Hardie Board Sheeting 50 square metres. This is old fascia board that will be getting tidied up, there will be a small amount of cement, based plaster used.

A. Resene can tint Resene New Denim for you. I recommend you try a testpot first to check you are happy with the colour.

If the sheeting is being used for an exterior of a building, apply one coat of Resene Pre-Coated Steel Primer followed by two full coats of Resene Summit Roof semi-gloss or Resene Lumbersider Low Sheen.

Cracks will need to be repaired and preferably sheets replaced prior to painting. If the current paint is sound, you can use two coats of Resene Lumbersider Low Sheen. Spot prime newly cement areas with Resene Limelock if under 28 days or Resene Sureseal or Resene Concrete Primer.

September 2023

Q. Is there a clear coat/sealer that one can apply to unpainted zincalume corrugated iron roofing/cladding that will reduce the LRV% from its natural 70% to 50%. Our client wants Zincalume look but needs to comply with 50% LRV for cladding and roofing.

A. No, Resene has no such product. You cannot change the LRV on a clear as it has no rating. The only option would be to repaint it in a similar but lighter colour.

September 2023

Q. I bought some Resene Roof and Metal Wash to clean long-run corrugated roof. There is a flat membrane to the side and below roof. The membrane is Viking Enviroclad. With this they say avoid petroleum products and solvents, grease and oils. Is Resene Roof and Metal Wash harmful to Viking Enviroclad?

A. Resene Roof and Metal Wash can be used on Enviroclad Membrane.

August 2023

Q. I’ve just primed a roof with oil-based primer. I am going to topcoat tomorrow with a spray gun. Do I need to rewash with Resene Roof and Metal Wash again?

A. You would only need to rewash between coats if it has been contaminated, you are in a coast area with lots of windblown sea salts, or it has been a while since applied the last coat (usually over seven days).

August 2023

Q. I have a roof with several small patches of rust. Do you have a rust converter or suitable rust killer paint that is OK to use with a roof used to collect drinking water?

A. Resene has Resene Rust-Arrest. The downpipes will need to be disconnected until the painting is complete and has had its first decent rain or wash before reconnecting.

August 2023

Q. Why is a bonded roof colour so it is changeable in the sun and different lights. Every time I look at my new roof it seems a different shade and can look quite odd.

A. This could be the sheen level contributing to this effect and colours looking different in different lights is common. Natural light can make colours look quite different.

July 2023

Q. I’m looking for a paint system to paint a roof with the blackest black but something that is sparkly (black glitter almost) is there such a thing?

A. We do have some options available on our Resene FX Metallics chart, such as Resene Blast Grey 1 and Resene Catch 22. These are made using our Resene FX Metallic base which is a waterborne enamel.

A suitable primer for a roof and any rust preparation is needed depending on the condition of the current roof then a base coat of Resene Lumbersider Low Sheen of a solid colour likely a charcoal or black, followed by two topcoats of the Resene FX Metallic in your desired colour choice.

These products can be brush or roll applied but spray gives the best finish as this helps to lay the metallic flakes all in the same direction, making a more uniform look.

July 2023

Q. Is it possible that paint chalking paint on a roof can wash off into water tanks and therefore affect drinking water? If so, is this potentially a health risk?

A. All paints chalk unfortunately. Yes, there will be a percentage that does dislodge and enter water tanks, but this is no more a health risk that bird droppings being washed off the surface of a roof into the tank.

We recommend once a year the downpipes are disconnected and the roof is washed, to decrease the build-up. This will remove many contaminants including chalking, windblown salts, droppings etc. Any moss and mould can be treated at this time also.

July 2023

Q. There is one way that Resene paints could help reduce global warming - produce a white roof paint. I have a building clad in iron sheets painted in a reddish brown colour. On summer afternoons the sun shining on these sheets severely heated the wall on the Inside of the room. If a person placed their hand on the inside wall they would experience a severe burn. One could literally fry an egg on this heated wall.

In order to mitigate this problem I painted this wall white. The difference was dramatic. The inside of this wall was just barely warm. So painting roofs white would help cool houses in the summer. If all roofs were painted white the overall effect would help reduce local and so global temperatures.

A. Resene through our innovative R&D have CoolColour technology. This assists in darker colours absorbing less infra-red and UV rays therefore not heating up as dramatically as the standard version of the colour.

Painting roofs white is a great start but cannot be done in airport flight path zones and is restricted in many areas because of the glare it can cause. Resene have roof paint options of Resene Summit Roof semi-gloss and Resene Hi-Glo which are both available in white and shades of, as well as the favoured darker colours.

July 2023

Q. I have a painter that is using your products for painting my tile roof. The first coat of paint was applied and I checked in the weekend and found that they had painted over the roof without cleaning it. I could see dead bees, grit, moss and other debris trapped under the paint. They have since water blasted and there are parts where the paint is peeling (as I suspected) and bugs still strapped under paint and loose moss that has not been washed or swept off the roof. They are saying they are ready to reapply the sealer and paint. I am suggesting that they might need to take it back to the original coating before rewashing the roof. As I am not home I can’t check on the compliance.

My question is what is your recommendation for the application?

Do you have people who can check on compliance or audit the paintwork as I can only go on from what I see? I also suspect they may not have washed the house before priming/sealing cedar as I was not home when the undercoats were put on.

They do provide a 5 year warranty but I suspect the paint may not last 5 years and then I have the hassle of chasing them up or it fails at the 5 year one day mark and I have no comeback

A. I would also recommend removing the primers and preparing the roof properly, this also includes killing the moss and mould and removing any lichen as water blasting does not kill the spores and they will come back and grow through your paint. There will also be other contaminants present like sea salts etc that should be washed away in conjunction with a cleaner. There are now contaminants trapped between the primer and the original roof coating.

Unfortunately, no we do not have a team that checks on applications, the Master Painters Association offers these services.

It’s hard to say what other prep may be required for your project, like rust treatments, specific primers etc, repairs, sealing fillers, etc. I would raise your concerns with the painter and ask them to address them.

July 2023

Q. How can we make our roof paint colour last longer?

A. Resene Summit Roof is our premium roof choice, changing the colour to a colour where the chalking will be less noticeable is an option when annual washing is not possible. Roofs should ideally be washed at least annually to keep the paintwork in good condition.

Otherwise, Resene Clearcoat UVS can be applied over a clean painted surface. This is a water-based U.V protective glaze (gloss finish) that can help to filter out harmful U.V light, which can help your roof colour look good for longer.

July 2023

Q. We are repainting our COLORSTEEL® roof. There is no flaking paint but the colour has just worn through to the undercoat/primer. How do I recoat it?

A. To paint aged COLORSTEEL® we recommend you clean with Resene Heavy Duty Paint Prep and Oil Remover and treat any moss and mould at this time with Resene Moss & Mould Killer. Apply one coat of Resene Precoated Steel Primer, followed by two topcoats of Resene Summit Roof semi-gloss in your desired colour.

May 2023

Q. Which product would you recommend to paint a ‘Super 6’ roof containing asbestos? This has been coated about 20 years ago and is in reasonably good condition, but needing to be done again.

A. We recommend disconnecting any downpipes while cleaning and recoating. Treat any moss and mould with Resene Moss & Mould Killer and wash down with Resene Paint Prep and Housewash. Please soft wash rather than water blast due to the asbestos. Apply one coat of Resene Sureseal to any bare areas where the paint has flaked or been removed. Apply two topcoats of Resene Summit Roof paint semi-gloss in your desired colour.

Below I will add some additional more in-depth information, regarding, asbestos , cleaning, and some dos and don’t’s:

Fibre Cement Cladding and Roofing containing ASBESTOS Before 1983, most fibrous cement in use in New Zealand contained asbestos. Fibrolite was reinforced with asbestos only. While James Hardies Hardiflex™ was reinforced with 4% asbestos and 4% wood fibre. Fibre cement products were used extensively for wall claddings on houses, garages etc., and also for corrugated roofing (the most common brand name being Super 6 roofing). Unless the exact age of the cladding/roofing can be established beyond doubt the assumption must apply that the material contains asbestos. These products pose a health hazard if care is not taken in surface preparation prior to painting or if just cleaning down.

Asbestosis is a chronic condition affecting the lungs and is caused by the inhalation and retention of asbestos fibres which results in scarring of lung tissue. Asbestosis is linked to almost all of the known types of asbestos fibres. Sufferers may experience severe shortness of breath and are at an increased risk of malignancies including lung cancer. It usually occurs after high intensity and/or long term exposure and is regarded as an occupational; lung disease.

See WorkSafe website for more details. Removal and/or disposal of asbestos containing materials (or just cleaning down of them) may require special permission and/ or a license. Contact your local Council offices to determine your obligations under their bylaws. Also refer to the Health and Safety at Work (Asbestos) Regulations 2016 or obtain a copy of the New Zealand Demolition and Asbestos Association publication New Zealand guidelines for the management and removal of asbestos available from the WorkSafe NZ website.

Release of free asbestos fibres into the environment as a result of surface preparation or cleaning must be avoided at all times.

The following procedures must be followed during the preparation and or cleaning of asbestos containing fibre cement cladding and roofing as part of any painting operation.

• Do not water blast asbestos containing claddings or roofing.
• Keep the surface and any detritus/debris damp.
• Do not use power tools except for removal of fixing screws.
• Do not break the sheets into smaller sections, either when removing or disposing of. Wherever possible remove the complete sheet.
• Wear personal protection equipment including disposable overalls and a suitable dust respirator.
• Collect and contain all debris washed off the substrate and maintaining in a wet state in a sealed container.
• Restrict access to personal other than those directly associated with preparation.
• Remove all asbestos containing material from site for disposal at a refuse site approved by the local authority. We strongly recommend that base line testing of air and ground samples is undertaken to establish if there is asbestos contamination prior to work commencing. Local authorities will need to be involved in decisions on sampling sites for a given location as some local bodies will require confirmation that there is no site or air contamination arising from preparation and subsequent painting operations.

Step 1: Treat moss and mould with Resene Moss & Mould Killer; use as directed on the label.

Note I: For heavy infestations, an additional application(s) may be needed.

Step 2: Apply a liberal wash of Resene Paint Prep and House Wash to the surface with a nylon bristle brush or broom and thoroughly scrub while ensuring that the surface remains wet at all times. Collect and contain wash off using filters placed either on the ground or at down pipe connections. The surface must remain damp while preparation work is under taken. Additionally do not allow debris to dry out and immediately place filters into tightly sealed heavy duty plastic bags for disposal Data Sheet D812

Step 3: Allow to the surface to dry out and then apply by roller or brush a saturation coat of Resene Sureseal - solventborne pigmented sealer to bare areas. The surface will be highly porous and will require significantly higher volumes of Resene Sureseal - solventborne pigmented sealer to saturate the surface (typically an applicate rate 4 to 6 square metres per litre, based on a flat surface).

March 2023

Q. I painted my corrugated iron roof about 15 years ago with Resene Hi-Glo paint in a rock colour. I now need to repaint it. Can you please advise the best Resene product to paint that with?

A. If the roof is in good condition with no bare patches or rust, we recommend washing with Resene Paint Prep and Housewash followed by either two coats of Resene Summit Roof paint semi-gloss or you can continue with Resene Hi-Glo if you prefer the gloss look.

March 2023

Q. I’ve got a 50 year old Decramastic roof that I want to repaint Resene Ironsand. It’s a dark brown at the moment. There are a few bald patches where the aluminium is showing through with a bit of surface rust. What paint would you recommend I get?

A. Upon weathering, the tiles will lose chip texture due to erosion of the bitumen base back to base metal which at the extreme will result in corrosion. This specification will restore colour but not the original chip texture profile. Some mastic and bitumen-based coatings used in the manufacture of pressed roofing tiles prior to the early 1980s may contain asbestos. Certain profiles which are likely to contain asbestos are Decramastic.

Arrange for a specialist to take samples and undertake testing to confirm the presence or absence of asbestos OR assume that asbestos is present.

If asbestos is present, any work must be carried out in accordance the following documents:

The Health and Safety at Work (Asbestos) Regulations 2016.

WorkSafe New Zealand Approved Code of Practice-Management and removal of Asbestos The Health and Safety at Work Act 2015 Note 1: If the presence of asbestos is confirmed all surfaces must remain wet whilst being worked on during all preparation steps.

Step 1: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding.

Step 2: Treat areas of moss/lichen infestation at least two weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time. Treat heavy infestations with a second application 4 hours after the first application and leave for at least 2 weeks before washing down with water, scrubbing to remove loose detritus (see Note: 1), then rinse with clean water.

Step 3: Wash down with water to remove all dirt, grease, moss and mould residue, dust, and other contaminants. WATER BLASTING IS NOT RECOMMENDED AS THIS WILL RESULT IN THE DISLODGEMENT OF CHIP. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes. Place a coarse filter on the exit section of the downpipe to capture chip and debris and then dispose of in accordance with asbestos guidelines.

Step 4: All paint that is flaking or unsound must be removed by wet sanding (see Note: 1) to a sound feathered edge taking care not to damage either the substrate or the surrounding areas. Remove all areas of white corrosion material and as much red rust as is practicable using mechanical methods, (3M Rust and Paint Removal Disc), taking care not to damage either the substrate or the surrounding areas. Where under-film corrosion is taking place, the existing coating must first be removed as per above and remove corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Spot prime prepared areas of corrosion/bare substrate with two coats of Resene Galvo-Prime and then finish with two coats of Resene Summit Roof.

Note this system will not restore the original chip profile.

March 2023

Q. Lichen exists on the roof. I can use Resene Moss & Mould Killer. We collect the water for drinking. How long after mould treatment can we collect water for drinking? How long after water blasting the mould could I start painting?

A. Disconnect roof downpipes until after the first shower of rain in order to flush away surplus non-toxic wetting agents before the surface is used for the collection of drinking water. Alternatively the roof can be washed to the point of a reasonable runoff, preferably over a sustained time rather than a short shower of rain for the best. Once treatment and cleaning of the roof has been completed, you can start painting once the surface is dry. Try not to paint in full sun but choosing the time of day wisely.

March 2023

Q. We have a Colorcote roof and one section requires resurfacing, it’s getting down to the galvanising. The coating and spec is ZRX finish. It’s southwest facing and the sea is approx 800m away.

A. We recommend washing first with Resene Paint Prep and Housewash. Then apply one coat of Resene Galvo One and two topcoats of Resene Summit Roof paint. Please wash thoroughly between all coat with Resene Paint Prep and Housewash to remove any wind-blown sea salts, especially if there are a few days between coats.

Salt is a serious contaminant on steel surfaces and wind can drive sea water, in aerosol form, many kilometres inland. Up to 100km inland has been recorded in windy New Zealand. As the majority of cities in Australasia, and all in Oceania, are coastal; the effect of windblown salt is ubiquitous. Salt, being readily water-soluble, is easily washed off smoother, impervious surfaces and natural rain washing mitigates the condition significantly. However, areas of low rainfall, such as the Australian West Coast, and anywhere after a long, dry period, should expect the presence of windblown salt. Of particular concerns is rain protected areas, such as steel under canopies and eaves.

March 2023

Q. We want to spray paint our concrete tiled roof (era 1986 colour red in good condition) in Resene Gauntlet. What Resene paint and system do you recommend that we use?

A. We recommend to treat any moss and mould with Resene Moss & Mould Killer followed by a thorough clean with Resene Paint Prep and Housewash. Once dry, spot prime any areas with exposed bare concrete with one coat of Resene Sureseal. Then recoat with two topcoats of Resene Summit Roof Commercial Spray Grade which is designed for airless spray application.

March 2023

Q. How do I paint the lead flashing on a tile roof? The house is c 1930s and the flashing was painted but is now peeling.

A. We recommend removing any flaking paint with 3M sanding disc or sandpaper.

Prime with one coat of Resene Galvo One, followed by two topcoats of either Resene Lumbersider Low Sheen or Resene Summit Roof semi-gloss.

March 2023

Q. I have used Resene Galvo One to prime my roof, but due to the wet weather I am unable to apply topcoats so the primer is still exposed. We are on tank water. My question is can I reconnect my water tanks to collect water with the Resene Galvo One exposed? Or do topcoats have to be applied prior to water collection?

A. Yes, you can re-connect them after a good flush of water has rinsed the surface thoroughly.

February 2023

Q. I live by the sea and find the water based roof paints go chalky and dull after a short time. Can you suggest an oil based roof paint or something more durable for coastal conditions?

A. Chalking as the name suggests is the appearance of a white dust like material on the surface of the point. This occurs as the binder (resin) system is broken down upon exposure to UV along with water. The time to onset of chalking is related to paint gloss level and resin type. In the same weathering conditions the onset of chalking is longer with a full gloss finish than a low gloss finish.

No paint will retain the same gloss and colour after undergoing extended weathering. Typically a painted surface will require a maintenance coat/s within 10 years to maintain aesthetics. The time frame is determined by level of exposure and paint type.

The angles of roofing can also accelerate the time to chalking, if the same paint is exposed at an angle of 45 degrees the rate of exposure to weathering is twice that of the same paint on a vertical exposure.

Using Resene Hi-Glo being a higher gloss should help longer term. We do not currently have an oil based option for a roof as this wouldn’t have any better chalk resistance long term.

Washing the roof annually using Resene Paint Prep and Housewash will remove chalky paint and salt build ups.

January 2023

Q. Can I use Resene Moss & Mould Killer on my butynol roof?

A. Yes, you can but ensure it is not a hot day or try and keep slightly damp. Ensure no water is collected for drinking or watering the garden. Alternatively, Resene Deep Clean is a superb long term product.

January 2023

Q. I have a 70 year old concrete tile roof on my house, we are rural on tank water. Recently I have waterblasted the roof due to the build-up of scum filling into our water tanks. To make it easier to clean in the future I would like to paint the roof. Currently the roof is a mix of unpainted tile (90%) and painted tile (10%). What products/methodology would you suggest for me to prep and paint this, taking into consideration our water run off fills our tanks.

A. Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 3: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label instructions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 4: Waterblast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to waterblast under the tiles. Allow the surface to dry thoroughly. All downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes.

Apply a saturation coat of Resene Sureseal on bare tiles and then two coats of Resene Summit Roof over the entire roof. Reconnect downpipes after a very good rain wash for water collection.

January 2023

Q. Our COLORSTEEL® roof has faded and the coating is eroding.

A. To repaint we recommend high powdered water blast to remove the remaining powder coating. This requires specialist equipment.

If the entire surface is not back to bare before repainting, we won't be able to offer long term assurances in the new paint system, as the new paint system will add surface tension and can cause the remaining powder coating to flake off.

Once the surface is bare you can apply one coat of Resene Galvo One followed by two coats of Resene Summit Roof paint.

December 2022

Q. Please provide advice on a paint system for an existing painted galvanised steel roof, with some surface red rust particularly on screw fixings. The existing paint is Resene Summit Roof paint.

A. We would recommend replacing the screws, as the sharp edges make preparation too hard, so you won't be able to stop the corrosion from continuing to occur.

As for the surface rust, being red rust, this indicates that the Galvanised protective layer is gone and is back to bare metal. We can apply a coating to protect layers but it won’t stop the corrosion from occurring. Our best recommendation is to treat any moss and mould with Resene Moss & Mould Killer. Then wash with Resene Paint Prep and Housewash, followed by one coat of Resene ArmourX GP Metal Primer and two topcoats of Resene Summit Roof.

November 2022

Q. We have some butynol on a roof which is shedding black stuff. Is there a product to clean it and coat it so it lasts longer? Also the water from this roof goes into our drinking water.

A. The black material is the carbon pigment used to colour the butynol, as the butynol ages there is a breakdown of the surface and this releases the carbon pigment. Disconnect roof downpipes prior to prep and completion of painting, reconnect after the first heavy shower of rain that has sufficient water to actually run off the painted surfaces for half an hour, in order to flush away surplus non-toxic wetting agents before the surface is used for the collection of drinking water. Thoroughly scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Rinse clean or hose down with copious amounts of fresh water ensuring all wash solution and surface chalk residues are removed.

Allow to dry then apply a coat of Resene Membrane Primer and finish with two coats of Resene Summit Roof in your topcoat colour.

June 2022

Q. What paint systems should we use over a COLORSTEEL® roof. The roof has been spot rust treated with galvanised steel primer solventborne. The house is 1990s. There is no flaking or peeling of the factory applied paint finish. It was only a couple of spots where lichen had lifted the paint. And around a couple of nails. The COLORSTEEL® is actually in really good nick but the builders report said rust prevention treatment is needed for the long term. We have decided to paint the whole roof.

A. Treat areas of moss/mould infestation with Resene Moss & Mould Killer diluted and used to label/data sheet instructions. For heavy infestations more applications may be needed. Scrub down using Heavy Duty Paint Prep and Oil Remover diluted and used to label instructions. Rinse clean or hose down with copious amounts of fresh water ensuring all wash solution and surface chalk residues are removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, to leave only soundly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Spot prime prepared areas of corrosion with a coat of Resene Pre-coated Steel Primer followed by a full coat of the primer and then finish with two coats of Resene Summit Roof topcoat colour.

June 2022

Q. Is there a paint specifically for butyl membrane roofing?

A. Prime with Resene Membrane Primer then any exterior waterborne topcoat paint such as Resene Lumbersider Low Sheen. When the primer meets the substrate the primer and the roller will take on a sulphurous odour. Do not back add any of the primer left over after completing the priming step back into the bulk container.

If the butyl rubber is old then scrub down using Paint Prep and Housewash diluted and used to label/data sheet. Rinse clean or hose down with copious amounts of fresh water ensuring all wash solution and surface chalk residues are removed.

Allow to dry before priming.

June 2022

Q. I have a house with a concrete tile roof. The roof has been treated with a moss kill system where the rain over a period of time cleans the roof. It was then sealed with a sealant in June last year. I want to establish whether it's realistic for me to spray then seal the roof with a protective sealant to stop weathering and UV damage to the tile roof. I am looking to do this myself.

A. We have a pigmented system for this but not a clear.

Weathered concrete/terracotta tile roofs are typically infested with mould, widespread lichen and moss growth. Removal of these are critical to achieving a successful long term decorative paint system.

Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 3: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 4: Water blast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to water-blast under the tiles. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes. Apply a full coat of Resene Sureseal and finish with two coats of Summit Roof.

June 2022

Q. We had a roof installed on our garage earlier this year and then had to immediately leave for the UK. We have just got back and it looks like the builder or roofer had attached something with duct tape to the roof flashing at the front. Just the duct tape residue remains and it looks a pigs ear. Are you able to tell me the best way to remove it without affecting the coating below please? I believe it has probably been like that for a few months, Your help would be most appreciated as it is an eyesore, being on the front of the garage. Product is COLORSTEEL® Sandstone Grey. We have put this question to COLORSTEEL® already and they suggested we contact you.

A. We often suggest using Dissolve It to remove adhesive tape residues. However, this may also soften/damage the COLORSTEEL® coating.

Given the time the tape has been present removal may be difficult. You may have to touch up the area after removing the tape residues.

June 2022

Q. I would like to paint my fibreglass roof sheeting what would you recommend me to use in your product range? The roof is old it looks like it’s been there for a while. We only been here for only two years.

A. My only concern is the protrusion of fibreglass matting fibres.

Treat areas of moss/mould infestation with Resene Moss & Mould Killer diluted and used to label/data sheet instructions. For heavy infestations more applications may be needed.

Scrub down using Paint Prep and Housewash diluted and used to label/data sheet. Do not allow the wash solution to dry out on the surface (this includes window glass and joinery). Rinse clean or hose down with copious amounts of fresh water ensuring all wash solution and surface chalk residues are removed. Do not allow runoff to enter wastewater drains.

Apply a coat of Resene Quick Dry and finish with two coats of Resene Summit Roof. I’m not sure of the fibreglass profile but rolling of the Resene Quick Dry will help lay down any protruding substrate fibres.

June 2022

Q. My metal roof was recently painted by a professional painting company. They applied Resene Hi-Glo waterborne gloss using a spray system. Two topcoats were applied. It took them approximately two hours to complete the paint job (apply two topcoats); this also included a half hour break between topcoats. The primer had been applied the day before.

However, I noticed that on the Resene Hi-Glo waterborne gloss container, it states that a two-hour minimum recoat time is required before the second coat should be applied. By not following the two-hour minimum recoat time, has the expected paint system life (quality) been compromised? Should the professional painters have followed the guidelines on the paint container? Or does the recoat time differ if a professional painter uses a spray system?

A. The drying of a waterborne paint is determined by temperature, humidity, and air flow. If brushing or rolling a second coat cannot be applied until the first coat has achieved sufficient curing so as not to be disturbed/damaged by application of the second coat.

When spraying the equivalent wet film thickness of two coats can be achieved in a single application. This does not compromise the durability of the paint film.

I recommend you monitor the roof and contact the painter if there are any signs of bubbling/flaking within 12 months of application.

April 2022

Q. We are making arrangements to repaint our 30-year old COLORSTEEL® roof. It's first re-paint. We are in Ngaio and get all day sun. Two painters have said the repaint will last about 10 years before it again needs a repaint. This is very disappointing considering the original factory applied paint has lasted 30 years. Providing proper cleaning and preparation, how long does Resene consider the topcoats should last if applied over Resene Galvo One.

A. Treat areas of moss/mould infestation with Resene Moss & Mould Killer diluted and used to label instructions. For heavy infestations more applications may be needed. Thoroughly scrub down using Resene Heavy Duty Paint Prep and Oil Remover diluted and used to label/data sheet. Rinse clean or hose down with copious amounts of fresh water ensuring all wash solution and surface chalk residues are removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, to leave only soundly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are prepared back to a sound feathered edge and immediately spot prime all areas of corrosion and any other bare metal with a full coat of Resene Pre-Coated Steel Primer. Then apply a full coat of Resene Pre-coated Steel Primer and finish with two coats of Resene Summit Roof.

The guaranteed time for COLORSTEEL® is usually 15 years, this is for corrosion protection not aesthetics. I would be surprised if your roof is not showing significant chalking and colour fade of the original factory paint system.

The time quoted by the painters is in line with our recommendations, however the time is for recoating to maintain aesthetics.

March 2022

Q. Your roof painting guide indicates that where rain water is collected for drinking purposes, downpipes should be disconnected until after a ‘decent shower of rain’. I wondered what ‘decent’ constituted? I have just finished painting our roof and have had 6mm of rain last night but none of it heavy. Is that sufficient?

A. The washing is to remove wetting agents from the fresh paint. Ideally a couple of rain showers is all that is required, as long as the painted surface gets thoroughly wet and the water runs off. We have not been able to use rain volume as a guideline for re connection. If you have a garden hose wash an area down, if the runoff is not foamy then this is consistent with removal of wetting agents.

March 2022

Q. I recently bought some of your Resene Roof and Metal Wash to clean/prep (for painting) some new unpainted galvanised window flashings we are having installed. I was wondering if it is ok to use this same product for our annual roof wash on 6 year old COLORSTEEL®? If ok, would you recommend the same or a weaker mix than the rate stated for unpainted galvanised steel?

A. Yes, Resene Roof and Metal Wash is suitable for both areas at the label dilution rate.

February 2022

Q. We have a bright green COLORSTEEL® roof. About 22 years old in a coastal environment. The colour is starting to come off in stripes. We want to repaint it as it is still in good condition. What preparation and paint do you recommend please?

A. Treat moss and mould with Resene Moss & Mould Killer following label instructions. For heavy infestations more applications may be needed.

Scrub down using Resene Roof and Metal Wash diluted and used to label instructions. Do not allow the wash solution to dry out on the surface (this includes window glass and joinery). High pressure water blast clean ensuring all wash solution and loose surface material is removed. Ensure all edges where paint is removed are prepared back to a sound feathered edge and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer. Spot prime bare metal with Resene Pre-Coated Steel Primer and finish with two coats of Resene Summit Roof.

I am unsure why the factory topcoat is failing, given this we cannot guarantee adhesion of the new paint system applied over any residual factory coating.

October 2021

Q. I need a solution to paint concrete roof tiles that will collect potable water. Collected water will be filtered by a Puretec filter system

A. Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding.

Step 3: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 4: Water blast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to water-blast under the tiles. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes. Apply a seal coat of Resene Sureseal and finish with two coats of Resene Summit Roof.

October 2021

Q. I wish to paint a protective coat(s) over my butynol flat roof. It’s not for waterproofing. It’s just to stop the sun's UV light ruining the butynol. And I think this would add extra life to the roof.

A. Scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Do not allow the wash solution to dry out on the surface (this includes window glass and joinery). Rinse clean or hose down with copious amounts of fresh water ensuring all wash solution and surface residues are removed.

Apply a coat of Resene Membrane Primer and finish with two coats of Resene Lumbersider Low Sheen. Use a CoolColour version of your topcoat colour if available in the colour you choose. A CoolColour system does not render the painted surface cool to touch. The CoolColour version of a colour will reflect more heat compared to the same colour made using non-cool pigmentation. The CoolColour system will reduce but not eliminate heat related stress on the substrate.

October 2021

Q. Our house has a decramastic tiled roof. The tiles are metal base with a bitumen/paint/chip finish. We have a small leak into the roof space. I have narrowed the leak area to about 300mm x 300mm and would like to apply a sealer and then a waterbased paint.

A. Paint will not seal off a leak. For painting a sound (free of bio growth) Decramastic roofing the primer is Resene Galvo-Prime followed by two coats of Resene Summit Roof.

August 2021

Q. How do we paint new COLORSTEEL® roof flashing so it matches our roof?

A. Scrub down using Resene Heavy Duty Paint Prep and Oil Remover diluted and used to label instructions. Do not allow the wash solution to dry out on the surface (this includes window glass and joinery). Rinse clean or hose down with copious amounts of fresh water ensuring all wash solution is removed. Apply a prime coat of Resene Pre-Coated Steel Primer and finish with two coats of Resene Summit Roof topcoat colour.

August 2021

Q. Would you suggest painting or staining new cedar roof tiles?

A. Staining is a high maintenance option and for cedar roofing tiles it may be an annual application of stain to maintain aesthetics and protection. Roofs are subject to more intensive weathering than vertical cladding and for this reason I would recommend painting with a solid paint system and if selecting dark colours a Resene CoolColour System.

The cedar must first be primed with Resene Wood Primer and then a coat of Resene Quick Dry and finish with two coats of Resene Summit Roof CoolColour topcoat.

To reduce the potential for cupping of the shingles I recommend you envelope prime all faces and particularly end cuts with Resene Wood Primer.

August 2021

Q. About 30 sqm of my roof is low pitch concrete tile roof and I need a very good waterproofing in that area, because the water is not discharging fast enough. Do you see any reason why I shouldn't use Resene X-200 on a concrete tile roof. Of course after applying Resene Sureseal pigmented sealer.

A. Resene X-200 is used to achieve weather tightness on vertical cementitious walls, it is not suitable for use where there will be water ponding. While the Resene Sureseal/Resene X-200 system may achieve what you are wanting we cannot give any guarantee for the system in this application.

August 2021

Q. How do I prepare and paint over an old concrete tile roof 60 years old still in the original condition?

A. Weathered concrete/terracotta tile roofs are typically infested with mould, widespread lichen and moss growth. Removal of these are critical to achieving a successful long term decorative paint system.

Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours.

Step 3: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent.

Resene Deep Clean is best applied under overcast conditions to maximise wetting time. Data Sheet D815

Step 4: Water blast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to water-blast under the tiles. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes. Once cleaned apply a seal coat of Resene Sureseal and finish with two coats of Resene Summit Roof colour.

August 2021

Q. We have a butynol roof. We intend to use Resene Membrane Primer then paint over the top. Can we use Resene X-200 as a roof paint instead of a normal roof paint? Our house is painted in Resene X-200 and we have found it to be easy to wash etc.

A. There is no reason why Resene X-200 could not be used as a roofing topcoat, but as a topcoat it is usually used for topcoating a cementitious substrate.

June 2021

Q. I have repainted some butyl roofing, previously painted. It has blistered. What product could I use to remove the paint layers without damaging the butyl?

A. Careful water blasting would be the only suggestion.

June 2021

Q. Please give me advice for painting a steel roof.

A. We have no specific painting video for roof painting. The key to achieving a successful roof paint project is preparation. The following information is based on the existing roofing being painted with a waterborne paint system.

Treat areas of moss/mould infestation with Resene Moss & Mould Killer diluted and used to label/data sheet instructions. For heavy infestations more applications may be needed. Treat areas of lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for at least 48 hours. Note this dilution will give a concentrated bleach solution, so care in mixing and use is required.

Thoroughly scrub down using Resene Paint Prep and Housewash diluted and used to label/data sheet. Rinse clean or hose down with fresh water ensuring all salts and surface chalk residues are removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, to leave only soundly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are prepared back to a sound feathered edge.

Spot prime all areas of corrosion and any other bare metal with two coats of Resene ArmourX GP Metal Primer and finish with two coats of Resene Summit Roof.

June 2021

Q. I have a COLORSTEEL® roof - big rib type - which is about 30 years old. There is quite a bit of delamination of the colour coating. What is the recommended repainting system in this situation?

A. A COLORSTEEL® roof of this age is probably due for replacement particularly if the roofing is located near the coast.

However if you are looking to retain the current roofing, treat areas of moss/mould infestation with Resene Moss & Mould Killer diluted and used to label/data sheet instructions. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Do not allow the wash solution to dry out on the surface (this includes window glass and joinery). High pressure water blast ensuring all salts, surface chalk and loose paint is removed.

After water blasting prepare edges of remain painting back to a sound feathered edge using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable using mechanical methods e.g. 3M Rust and Paint Removal Disc, to leave only soundly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Suggest that you undertake the prep and then send a photo of the outcome as this will dictate the priming system to possibly extend the life of the roofing.

June 2021

Q. How do I paint a metal roof?

A. The key to achieving a successful roof paint project is preparation. The following information is based on the existing roofing being painted with a waterborne paint system.

Treat areas of moss/mould infestation with Resene Moss & Mould Killer diluted and used to label instructions. For heavy infestations more applications may be needed. Treat areas of lichen infestation with Moss & Mould Killer diluted 1:1 with water and leave for at least 48 hours. Note this dilution will give a concentrated bleach solution, so care in mixing and use is required.

Thoroughly scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Do not allow the wash solution to dry out on the surface (this includes window glass and joinery). Rinse clean or hose down with fresh water ensuring all salts and surface chalk residues are removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, to leave only soundly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are prepared back to a sound feathered edge.

Spot prime all areas of corrosion and any other bare metal with a two coats of Resene ArmourX Metal Primer and finish with two coats of Resene Summit Roof.

June 2021

Q. I am hoping to repaint my corrugated iron roof in the next month or so. There is some rust in the roof but not too much and I think it is reasonably superficial. I have sanded it off in a few places to test it but it is hard work and I believe that sanding will remove the galvanising from the corrugated iron. Is there some sort of rust treatment that I can use to stop the rust?

The existing paint seems to be reasonably attached to the roof. I have tested it with some sticky tape and it seems OK and water blasting will get rid of any loose paint. With the priming do I need to spot prime or is there any paint like your Resene Quick Dry primer undercoat that could be used on a corrugated iron roof and act as both primer and undercoat as it will obviously be a lot easier to simply use the roller to apply a primer/undercoat than to spot prime.

A. Prep is the key to a successful roof painting project.

Treat areas of moss/mould/lichen infestation with Resene Moss & Mould Killer diluted and used to label/data sheet instructions. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label directions. Do not allow the wash solution to dry out on any surface. Waterblast clean or hose down with fresh water ensuring all salts and loose surface material is removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, to leave only soundly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are prepared back to a sound feathered edge and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer. We do not recommend use of ruts converters as our long-term experience with this type of treatment has shown that it does not offer the conversion that these products claim. Resene has no direct to substrate roof paints, while they do exist you will note in the small print on labels of opposition paints that claim DTM that priming is required where there is corrosion present.

The Resene system would be to undertake the above prep and over coat prepared areas of corrosion and bare metal with Resene ArmourZinc 110, overcoat areas primed with Resene Armourzinc 110 with a seal coat of Resene Galvo One then finish with two coats of Summit Roof.

March 2021

Q. I have an unpainted weathered tile roof. How do I repaint it?

A. I recommend you follow the following advice:

Weathered concrete/terracotta tile roofs are typically infested with mould, widespread lichen and moss growth. Removal of these are critical to achieving a successful long term decorative paint system.

Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 3: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time. Data Sheet D815

Step 4: Water blast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to water-blast under the tiles. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes.

Apply a seal coat of Resene Sureseal and finish with two coats of Resene Summit Roof.

March 2021

Q. I am repainting a butynol roof. Should I prime the whole area first (I have the Resene Membrane Primer) or just where the paint has lifted?

A. You should only prime exposed butynol with Resene Membrane Primer.

February 2021

Q. I am repainting my garage and house roof. There are some areas of red rusting coming through the paint. I have washed down with Resene Roof and Metal Wash and have applied Resene Rust Arrest to the rusted areas. Do I need to apply anything else before I can paint with two coats of Resene Summit Roof paint?

A. As long as you have not applied the Resene Rust Arrest to bare galvanising or zincalume you can then apply two topcoats of Resene Summit Roof.

February 2021

Q. We are instructed to assist in the handling of an insurance claim involving cosmetic damage to COLORSTEEL® MAXX cladding. The cladding was scratched during installation some time ago and the installer used touch up paint to conceal the scratches. As would be expected the touch up paint has faded at a differential rate from the panels and the aesthetic is no longer satisfactory. I am trying to identify an approved paint system and application contractor for the repainting of COLORSTEEL® MAXX cladding in an exposure zone 3 environment.

A. Pigments used to produce a paint colour in a factory applied paint system are highly likely to be different from pigments used to match in a wet paint finish. Are you sure that this is a fading issue and not a chalking issue? The way to differentiate is to wet the surface, if the original colour is seen with the wetted area then the issue is chalking due to weathering, if not then it is true colour fade. The other way is to wash down an area down using Resene Paint Prep and Housewash diluted and used to label directions. Do not allow the wash solution to dry out on the surface. Scrub while wet and rinse clean or hose down with fresh water ensuring all salts are also removed. Again, if the original colour is present on the washed area then it is chalking not fading.

The best system for adhesion/colour retention/durability is as follows;

Prep

Treat areas of moss/mould infestation with Resene Moss & Mould Killer diluted and used to label instructions. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label directions. Do not allow the wash solution to dry out on the surface. Rinse clean or hose down with fresh water ensuring all salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, to leave only soundly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place, the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are prepared back to a sound feathered edge and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer.

Apply a full coat of Resene Pre-Coated Steel Primer, two coats of Resene Summit Roof colour and finish with a full coat of Resene Clearcoat UVS.

February 2021

Q. Recently house painters dropped fresh paint and paint scrapings on to our COLORSTEEL® roof. They also over sprayed paint on to the roof. The paint was left to ‘bake on’. The paint is Resene white semi-gloss acrylic. We are seeking advice on how the paint can be removed without damaging the surface of the COLORSTEEL®.

A. Solvent wiping with meths may work but we cannot give any guarantees that the factory colour will not be affected. Use of meths for this application will be difficult as the solvent will evaporate quickly. The other consideration is that if the roof coating is damaged then the COLORSTEEL® warranty is negated.

February 2021

Q.I own a home with a decramastic tile roof that I'm looking to repaint by airless spray in the next few months. I'm intending to topcoat with Resene Summit Roof Commercial Spray satin however I'm not 100% on the correct primer for the intact coating on the tiles.

A. Upon weathering the tiles will lose chip texture due to erosion of the bitumen base back to base metal which at the extreme will result in corrosion. This specification will restore colour but not the original chip texture profile. Some mastic and bitumen-based coatings used in the manufacture of pressed roofing tiles prior to the early 1980s may contain asbestos. Certain profiles which are likely to contain asbestos are Decramastic and early Harvytiles.

Arrange for a specialist to take samples and undertake testing to confirm the presence or absence of asbestos OR assume that asbestos is present.

If asbestos is present, any work must be carried out in accordance the following documents:

• The Health and Safety at Work (Asbestos) Regulations 2016.
• WorkSafe New Zealand Approved Code of Practice-Management and removal of Asbestos
• The Health and Safety at Work Act 2015

Note 1: If the presence of asbestos is confirmed all surfaces must remain wet whilst being worked on during all preparation steps.

Step 1: Spot treat areas of heavy lichen infestation with Resene Moss and Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 2: Treat areas of moss/lichen infestation at least two weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time. Treat heavy infestations with a second application four hours after the first application and leave for at least two weeks before washing down with water, scrubbing to remove loose detritus (see Note: 1), then rinse with clean water.

Step 3: Wash down with water to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Water blasting is not recommended as this will result in the dislodgment of chip. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes. Place a coarse filter on the exit section of the downpipe to capture chip and debris and then dispose of in accordance with asbestos guidelines.

Step 4: All paint that is flaking or unsound must be removed by wet sanding (see Note: 1) to a sound feathered edge taking care not to damage either the substrate or the surrounding areas. Remove all areas of white corrosion material and as much red rust as is practicable using mechanical methods, (3M Rust and Paint Removal Disc), taking care not to damage either the substrate or the surrounding areas. Where under-film corrosion is taking place, the existing coating must first be removed as per above and remove corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Spot prime bare bitumen and prepared areas of corrosion with Resene Galvo-Prime then apply a full coat of Resene Galvo-Prime before topcoating.

December 2020

Q.We are having the roof of our house repainted. The roof has been water blasted to remove loose paint. However we have found that some of the flakes of paint that the water blaster has removed have adhered themselves back onto the roofing iron (zincalume) surface and it would appear that additional water blasting will not remove them. We would be extremely grateful for any advice on the flake removal, or if we should just paint over these flakes.

A.This is an unusual outcome. The only explanation is that the flakes are waterborne and were not flushed off the roof - when two waterborne paint finishes come into contact they can fuse. I recommend that the flakes are removed by using mechanical methods, (3M Rust and Paint Removal Disc). This will be slow but is the only way to remove.

November 2020

Q. We have a roof that needs repainting. It is galvanised (I think COLORSTEEL®) steel about 30 years old. Some people suggest water blasting then painting and others say absolutely not to water blast. What is the best prep and paint process?

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label instructions. Leave for up to 48 hours to achieve full kill. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Thoroughly scrub the surface with a stiff nylon broom to ensure complete removal of all grease, moss and mould residue, and any other contaminants, then rinse with copious amounts of fresh water or high pressure water blast ensuring all loose paint and salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blast taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), to leave only tightly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place, the existing paint must first be removed as previous methods including under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

November 2020

Q. We are going to paint our 15 year old COLORSTEEL® shed, it is a faded blue and we would like to paint it ebony black using a spray gun. Can you recommend a method and what paints to buy?

A. Scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Thoroughly scrub the surface with a stiff nylon broom to ensure complete removal of all grease, moss and mould residue, and any other contaminants, then rinse with copious amounts of fresh water or high pressure water blast ensuring all loose paint and salts are also removed.

Then apply a full coat of Pre-coated Steel Primer and finish with two coats of Resene Summit Roof topcoat CoolColour formulation. For application by airless spray Resene Summit Roof Spray Additive must be used. Use an airless unit such as a Graco 395 capable of achieving a minimum flow rate of greater than 2 litres per minute. Spray set up Summit Roof Semi-Gloss FFLP 516 tip, 60 mesh filter @ 1800 psi.

This recommendation is based on the assumption that the aged factory paint system is sound. Application of a Resene CoolColour will reflect more heat than the same colour made using non-cool pigmentation and reduce heat related stress on the substrate; it will not make the painted surface cool to touch.

November 2020

Q. Is there a Resene roof paint that can be used on a COLORSTEEL® corrugated iron roof that has oxidised and, if so, is there a preparatory coat that needs to be used first? Also, does Resene have a paint that deals with surface rust on the same material?

The roof age varies but predominantly 25+ years. The roof colour didn't lift but has just faded badly. It has already been painted once and has a mould engrained at present in certain places. Some areas, such as down pipe exits, have rust stains.

A. Scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Thoroughly scrub the surface with a stiff nylon broom to ensure complete removal of all grease, moss and mould residue, and any other contaminants, then high pressure water blast ensuring all loose paint and salts are also removed.

Remove all areas of red rust as is practicable by using mechanical methods, (3M Rust and Paint Removal Disc) to leave only tightly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Apply two coats of Resene Galvo One and finish with two coats of Resene Summit Roof. With a COLORSTEEL® roof of this age there is no guarantee of a 100% successful painting outcome.

September 2020

Q. How do I repaint a galvanised roof that is rusting?

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label instructions. Leave for up to 48 hours to achieve full kill. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Thoroughly scrub the surface with a stiff nylon broom to ensure complete removal of all grease, moss and mould residue, and any other contaminants, then rinse with copious amounts of fresh water or high pressure water blast ensuring all loose paint and salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blast taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), to leave only tightly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place, the existing paint must first be removed as previous methods including under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Spot prime prepared areas of corrosion and bare galvanising with a coat of Resene ArmourX GP Metal Primer (two coats of extensive red rusting) then finish with two coats of Resene Summit Roof.

September 2020

Q. Can I paint high gloss ceramic roof tiles?

A. Yes, you can.

Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss and Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 3: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 4: Water blast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to water-blast under the tiles. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes.

Apply an adhesion coat of Resene ConcreteSeal 3 in 1 and finish with two coats of Resene Summit Roof.

September 2020

Q. We have a traditional but old terracotta (orange) concrete tile roof. Some tiles have had to be replaced but different colours. Do you have a paint that will match?

A. The following can be used to paint un glazed tiles;

Weathered concrete/terracotta tile roofs are typically infested with mould, widespread lichen and moss growth. Removal of these are critical to achieving a successful long term decorative paint system.

Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss and Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

D80 Step 3: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 4: Water blast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to water-blast under the tiles. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes.

Apply a seal coat of Resene Sureseal then finish with two coats of Resene Summit Roof.

September 2020

Q. Do you have a paint system that can be used on foil underlay on roofs?

A. Try Resene Vinyl Etch white.

September 2020

Q. What do you recommend for my 22 year old deteriorated fibreglass roof? It’s an exterior sheet of clear roofing, fibreglass plastic.

A. My only suggestion would be to clean down using Resene Paint Prep and Housewash diluted and used to label instructions and apply 2 or 3 coats of Resene Clearcoat UVS.

August 2020

Q. As part of painting a roof would like to clean a Novalite section of it. Can I use Resene Moss & Mould Killer on Novalite or will it affect the finish?

A. Re the Novalite, if there is moss/mould present then the Resene Moss & Mould Killer is the only option. Clean using Resene Paint Prep and Housewash diluted and used to label instructions.

August 2020

Q. Do I need to use a primer to paint a COLORSTEEL® corrugated roof Iron that is about 25 years old?

A. Yes, the main reason is to extend the corrosion performance. Wash down using Resene Paint Prep and Housewash diluted and used to label directions then apply a full coat of Resene Pre-coated Steel Primer and follow with two coats of Resene Summit Roof.

May 2020

Q. I have painted part of my roof and the day went from beautiful to high cloud and cool. It seemed like the paint had dried, then light rain in the morning now there are bubbles, some large. How do I fix this?

A. At this time of the year painting late in the day and on southern elevations are environmental conditions which do not allow the wet paint film to fully form to a film that will resist moisture contact usually in the form of dew fall. Sometimes the blisters will disappear without compromising the durability of the new paint however if the blisters persist then the only remedy is to scrape them off and repaint.

May 2020

Q. I have an older corrugated roof that needs a paint, so I have been 'researching' how to go about doing it myself. It has been previously painted with water based paint in one section and oil based paint in another section. There are a few patches (on both areas) that will need decent rust inhibiting protection, but overall the roof is generally sound.

A. To follow is our standard prep for repainting metallic substrates including roofing;

If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label instructions. Leave for up to 48 hours to achieve full kill. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label instructions. Thoroughly scrub the surface with a stiff nylon broom to ensure complete removal of all grease, moss and mould residue, and any other contaminants, then rinse with copious amounts of fresh water or high pressure water blast ensuring all loose paint and salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water blast taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc),to leave only tightly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place, the existing paint must first be removed as previous methods including under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

May 2020

Q. Which type of paint is suitable for painting a decramastic roof?

A. Spec Sheet 5:8/3 – Painting aged Decramastic tile roofs

Upon weathering the tiles will lose chip texture due to erosion of the bitumen base back to base metal which at the extreme will result in corrosion. This specification will restore colour but not the original chip texture profile. Some mastic and bitumen-based coatings used in the manufacture of pressed roofing tiles prior to the early 1980s may contain asbestos. Certain profiles which are likely to contain asbestos are Decramastic and early Harvytiles.

Arrange for a specialist to take samples and undertake testing to confirm the presence or absence of asbestos OR assume that asbestos is present.

If asbestos is present, any work must be carried out in accordance the following documents:

• The Health and Safety at Work (Asbestos) Regulations 2016.
• WorkSafe New Zealand Approved Code of Practice-Management and removal of Asbestos
• The Health and Safety at Work Act 2015

Note 1: If the presence of asbestos is confirmed all surfaces must remain wet whilst being worked on during all preparation steps.

Step 1: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3

Step 2: Treat areas of moss/lichen infestation at least two weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time. Treat heavy infestations with a second application 4 hours after the first application and leave for at least 2 weeks before washing down with water, scrubbing to remove loose detritus (see Note: 1), then rinse with clean water

Step 3: Wash down with water to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Water blasting is not recommended as this will result in the dislodgement of chip. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes. Place a coarse filter on the exit section of the downpipe to capture chip and debris and then dispose of in accordance with asbestos guidelines.

Step 4: All paint that is flaking or unsound must be removed by wet sanding (see Note: 1) to a sound feathered edge taking care not to damage either the substrate or the surrounding areas. Remove all areas of white corrosion material and as much red rust as is practicable using mechanical methods, (3M Rust and Paint Removal Disc), taking care not to damage either the substrate or the surrounding areas. Where under-film corrosion is taking place, the existing coating must first be removed as per above and remove corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Spot prime areas of prepared corrosion with Resene Galvo-Prime then apply a full coat of Resene Galvo-Prime and finish with two coats of Resene Summit Roof.

May 2020

Q. What type of paint do I need for a corrugated iron roof. It’s only small, approximately 2x3 metres. The colour required is Resene Gravel.

A. I recommend you use Resene Summit Roof.

April 2020

Q. Which products will I need to paint an unpainted uncorrugated iron roof on a villa – the iron is not new but in good condition?

A. Wash down using Resene Roof and Metal Wash diluted and used to label instructions then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof.

April 2020

Q. I've gone and left the first coat of Resene Summit Roof sitting for a month. Will it need any special treatment before the second coat goes on?

A. Wash down using Resene Paint Prep and Housewash diluted and used to label instructions before painting.

April 2020

Q. Is your roof paint suitable for cover on malthoid shingles ?

A. Prime the malthoid with a coat of Resene Membrane Primer before topcoating with a waterborne topcoat.

April 2020

Q. What Resene paint would be suitable for a Butynol roof and if needed what primer or undercoats would be needed? The roof is 4 years old and I am wishing to paint it to protect it and therefore increase its life span.

A. Wash down using Resene Paint Prep and Housewash diluted and used to label directions then apply a coat of Resene Membrane Primer followed by two coats of Resene Lumbersider colour. The paint system is purely decorative and will not change the water tightness of the butynol roofing.

April 2020

Q. I have Butynol covered roof dormers and want to paint them – can you recommend a type of paint that is suit?

A. Scrub down the butynol using Resene Paint Prep and Housewash then apply a coat of Resene Membrane Primer and finish with two coats of Resene Lumbersider or Resene Sonyx 101. Use the CoolColour version if using a darker colour. Application of a Resene CoolColour will reflect more heat than the same colour made using non-cool pigmentation and reduce heat related stress on the substrate; it will not make the painted surface cool to touch.

April 2020

Q. My garage galvanised corrugated iron has some areas of surface rust, no holes or leaks. I want to repaint my roof.

How do I treat the rust and then what primer and topcoat should I use? I am not able to climb on my roof to wire brush the rusted areas so would prefer a chemical treatment if possible.

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label/data sheet instructions. Leave for up to 48 hours to achieve full kill. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label/data sheet instructions. Thoroughly scrub the surface with a stiff Nylon broom to ensure complete removal of all grease, moss and mould residue, and any other contaminants. Rinse or water blast clean with fresh water ensuring all salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blast taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc) to leave only tightly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place, the existing paint must first be removed as previous methods including under film corrosion products taking care not to damage sound zinc coated areas.

All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Spot prime prepared areas of corrosion and bare metal with Resene GP Metal Primer then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof.

March 2020

Q. I have an unpainted zincalume roof on my garage which has light surface rust forming. I am after some advice on how to best deal with it. I am not near a coastal area and understand that rust is very hard to eliminate.

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label/data sheet instructions. Leave for up to 48 hours to achieve full kill. For heavy infestations more applications may be needed.

Scrub down using Resene Roof and Metal Wash diluted and used to label/data sheet instructions. Thoroughly scrub the surface with a stiff Nylon broom to ensure complete removal of all grease, moss and mould residue, and any other contaminants, then high pressure water blast ensuring all lose paint salts are also removed.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc) to leave only tightly adherent corrosion products taking care not to damage either the substrate or the surrounding areas.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Spot prime prepared areas of red corrosion with Resene GP Metal Primer then apply a fill coat of Resene Galvo One. Then finish with two coats of Resene Summit Roof.

March 2020

Q. I have a green roof which needs a repaint of acrylic paint. It is older corrugated roof with imperfections. What would be the best option in terms of gloss or semi-gloss?

A. In general terms lower gloss level paint finishes will assist to hide surface defects, however with roofs certain roof pitches may still show imperfections due to the angle light hits the roof. We recommend Resene Summit Roof for roofing.

March 2020

Q. We want to repaint a COLORSTEEL® roof. What do you recommend?

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label/data sheet instructions. Leave for up to 48 hours to achieve full kill. For heavy infestations more applications may be needed.

Scrub down using Resene Heavy Duty Paint Prep and Oil Remover diluted and used to label/data sheet. Thoroughly scrub the surface with a stiff Nylon broom to ensure complete removal of all grease, moss and mould residue, and any other contaminants, then rinse with copious amounts of fresh water or high pressure waterblast ensuring all loose paint salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblast taking care not to damage either the substrate or the surrounding areas.

Then apply a full coat of Resene Pre-Coated Steel Primer and finish with two coats of Resene Summit Roof.

March 2020

Q. For a decramastic roof, which paint is best – Resene Summit Roof or Resene Lumbersider? If Resene Lumbersider is the right option, is CoolColour the way to go?

I will be spot priming using Resene Galvo-Prime as it’s waterborne and won't affect the bitumen. I want a low sheen finish and will be using an airless sprayer.

A. Resene Summit Roof is our roof paint option, when using dark colours on any exterior substrate we recommend using the CoolColour version of the topcoat colour. Application of a Resene CoolColour will reflect more heat than the same colour made using non-cool pigmentation and reduce heat related stress on the substrate; it will not make the painted surface cool to touch.

Resene Summit Commercial is targeted for airless application by trade customers with the required airless spray set up.

February 2020

Q. I'm having a new zincalume roof put on a shed. I read the Resene leaflet which mentioned that zincalume had a 'form oil' on it which interfered with painting and should be removed. How do I remove it? Is it best to paint the zincalume immediately, or to let it weather slightly first?

A. Wash the roof down using Resene Roof and Metal Wash diluted and used to label instructions then apply a primer coat of Resene Galvo-Prime and finish with two coats of Resene Summit Roof. The new roof is best prepared and painted as soon as possible after installation.

February 2020

Q. Which primer do I use on an old weathered (but in good condition) COLORSTEEL® roof, prior to applying Resene Summit Roof CoolColour by airless sprayer? I have de-moulded and washed it down as advised. I want to spray the primer on as it's a big roof!

A. We recommend Resene Pre-Coated Steel Primer.

February 2020

Q. The south side of my roof (10-15 year-old COLORSTEEL® I believe) appears as though it is degrading as it has white patches. The patches don't actually feel flaky by hand at all. Which paint-system approach would you recommend for repainting? The house is around 500 metres from a heavy-salt-surf beach.

A. The white material is zinc corrosion products arising from corrosion of the base metal cladding and is not unexpected given the age and location of the roof. There is a chance that there are other areas with under film corrosion which may not as yet broken through.

For spot repairs wash down using Resene Roof and Metal Wash diluted used to label instructions. Remove all areas of white corrosion material using mechanical methods e.g. 3M Rust and Paint Removal Disc, taking care not to damage either the substrate or the surrounding areas. Spot prime the prepared areas of corrosion with two coats of Resene GP Metal Primer and then apply two coats of Resene Summit Roof.

February 2020

Q. Comparing Resene Summit Roof and Resene Hi-Glo for painting steel roofs, is the Resene Hi-Glo more resilient but more slippery to walk on? Can I apply Resene Galvo One and these paints at 95% humidity?

A. I doubt if there will be a great difference between the wet slip resistance of Resene Summit Roof and Resene Hi-Glo despite the gloss difference. Roof pitch will also be a key determinant of slip potential.

Resene Galvo One is our recommended primer for older roofs.

Waterborne paints cannot be applied when relative humidities exceed 85% during application or for at least the first 24 hours post application. This is to ensure the environmental conditions to facilitate correct film formation.

January 2020

Q. I want to help a retired lady paint her roof. It is brownbuilt iron that has likely been painted over several times. It still seems to be attached to each layer though, but chalky. It has a good growth of lichen in places on it and some localised rusting patches that I will address with rust converter and epoxy resin. Would you suggest I give the roof a good water blast and is a primer necessary or will a good roof paint suffice?

A. Lichen kill and removal is the first step. While waterblasting may remove the lichen growth it will leave spores that will re grow over time. The most effective way to achieve this is to apply Resene Deep Clean following label instructions and leave for a month then waterblast. Heavy lichen growth can result in the lichen break through and weaken the adhesion of the existing paint system.

Then follow these prep steps:

Scrub down using Resene Paint Prep and Housewash and used to label instructions. Rinse clean or hose down with fresh water ensuring all salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, taking care not to damage either the substrate or the surrounding areas. Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are sound and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer.

Spot prime prepared areas of corrosion and bare metal with two coats of Resene GP Metal Primer and finish with two coats of Resene Summit Roof.

Paint adhesion will always be compromised on this roof cladding in areas where prolonged water ponding occurs.

January 2020

Q. I am proposing to use Resene Alumastic high build epoxy on patches of surface rust on my galvanised corrugated iron roof, probably a total area of less than 2%. I will use an angle grinder with wire brush to remove as much as possible and then apply two coats of Resene Alumastic with a brush. Can you tell me how best to clean before application? I could use a dry rag, otherwise Resene Roof and Metal Wash, which will mean wetting the bare metal surface.

A. The key requirements for preparing a corroded surface for painting is to remove salts and loose corrosion products. Salts can be removed by washing down using Resene Roof & Metal Wash diluted and used to label instructions. We now prefer to use a 3M Rust and Paint Removal Disc (drill fitted) for removing loose corrosion deposits, unlike a wire brush the 3M disc does not scratch the surface and is very effective at leaving only tightly adherent corrosion products on the surface. Resene Alumastic is a barrier coating so ensure you apply a thick coating for each coat.

December 2019

Q. Which products can I use to clean and paint my house's corrugated aluminium roof? There is very little of the original paint left so it's mostly bare metal.

A. Wash down using Resene Roof and Metal Wash to label instructions. You could then water blast to remove any reaming loose paint. Then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof.

December 2019

Q. We live in sight of the sea (though not directly beachfront). Do you have a recommendations about durability between your Resene Hi-Glo and Resene Summit roof paints in these circumstances? I quite like the look of your Summit metallic range (most likely the aluminium colour). Would that change your recommendations about durability?

A. It is essential to remove surface salt by washing down using Resene Roof and Metal Wash following label instructions. Prepare areas of flaking paint back to a sound edge using a 3M Rust and Paint Removal Disc.

Spot prime these areas with two coats of Resene GP Metal Primer in preparation for topcoating.

Re topcoating, for many years Resene Hi-Glo was marketed as a house and roof paint. However the lower gloss level of precoated factory roofing saw customer resistance to a high gloss roof paint finish so we introduced Summit Roof which is our reduced gloss level roof paint. In theory the higher the gloss level the longer the time to the onset of surface chalking, With roofing this is an important consideration and the roof pitches can see a roof elevation receiving at least twice the exposure level compared to a vertical cladding. Given this I would go with Resene Hi-Glo but you must decide on what gloss level best fits your acceptance.

December 2019

Q. I painted my roof about two years ago. It had rust at the time in patches and I used a rust converter then painted it. Now I have rust spots back again in the same places. What did I do wrong? How do I fix it properly this time so I won't have to keep painting rust every couple of years?

A. Unfortunately the term 'rust convertor' does not equate to rust stability. Resene Paints has not introduce such a convertor as we believe that they can have a hit and miss approach despite the branding.

If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer, diluted and used to label directions. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label directions. Rinse clean or hose down with fresh water ensuring all salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are sound and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer.

Spot prime the prepared bare metal/corroded areas with two coats of Resene GP Metal Primer before applying two coats of Resene Summit Roof.

December 2019

Q. I would like to get some advice regarding painting my decramastic roof? What products would I require?

A. Upon weathering the tiles will lose chip texture due to erosion of the bitumen base back to base metal which at the extreme will result in corrosion. This specification will restore colour but not the original chip texture profile. Some mastic and bitumen-based coatings used in the manufacture of pressed roofing tiles prior to the early 1980's may contain asbestos. Certain profiles which are likely to contain asbestos are Decramastic.

Arrange for a specialist to take samples and undertake testing to confirm the presence or absence of asbestos OR assume that asbestos is present.

If asbestos is present, any work must be carried out in accordance the following documents:

• The Health and Safety at Work (Asbestos) Regulations 2016.
• WorkSafe New Zealand Approved Code of Practice-Management and removal of Asbestos
• The Health and Safety at Work Act 2015

Note 1: If the presence of asbestos is confirmed all surfaces must remain wet whilst being worked on during all preparation steps.

Step 1: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 2: Treat areas of moss/lichen infestation at least two weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label directions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time. Treat heavy infestations with a second application 4 hours after the first application and leave for at least 2 weeks before washing down with water, scrubbing to remove loose detritus (see Note: 1), then rinse with clean water.

Step 3: Wash down with water to remove all dirt, grease, moss and mould residue, dust, and other contaminants. WATER BLASTING IS NOT RECOMMENDED AS THIS WILL RESULT IN THE DISLODGEMENT OF CHIP. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes. Place a coarse filter on the exit section of the downpipe to capture chip and debris and then dispose of in accordance with asbestos guidelines.

Step 4: All paint that is flaking or unsound must be removed by wet sanding (see Note: 1) to a sound feathered edge taking care not to damage either the substrate or the surrounding areas. Remove all areas of white corrosion material and as much red rust as is practicable using mechanical methods, (3M Rust and Paint Removal Disc), taking care not to damage either the substrate or the surrounding areas. Where under-film corrosion is taking place, the existing coating must first be removed as per above and remove corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Spot prime prepared areas of corrosion/bare substrate with two coats of Resene Galvo-Prime and then finish with two coats of Resene Summit Roof.

Note this system will not restore the original chip profile.

December 2019

Q. What sort of paint should I use on an old unpainted galvanised metal roof? There is some surface rust.

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label directions. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label directions. Rinse clean or hose down with fresh water ensuring all salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are sound and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer.

Prime prepared corroded areas with Resene GP Metal Primer then apply a full coat if Resene Galvo One and finish with two coats of Resene Summit Roof.

December 2019

Q. I am looking for a coating for the tanalised cedar shingle on my roof that will prevent the CCA treatment leaching into the tanks we rely on for our water supply. Any coating would have to be totally non-toxic, stable and not dissolve when exposed to rain and U.V for long periods.

Some shingles have been in place and weathering for a year, others will be entirely new.  I have been unable to source untanalised shingles and for various reasons alternative roofing materials are not practical.

A. A possible system is to apply a prime coat of Resene Wood Primer and then to apply 2 coats of Resene Summit Roof.

Disconnect roof downpipes until after the first shower of rain in order to flush away surplus non-toxic wetting agents before the surface is used for thecollection of drinking water. The paint system will only be effective on areas accessible to paint.

Q. Our painter quoted to spray our roof with two coats of Resene paint, however he has come back to us and said he wants to do one heavy coat instead.  He will be brush painting the edges butting up against the Gutter guard.  Is spraying two coats better than one heavy coat or vice versa?

A. Most roof coating undertaken by commercial trade painters is by spray application and a single spray application to achieve the wet film thickness of two coats is now becoming the norm.

Q. I'm looking to paint my concrete roof tiles this summer.  The tiles are about 28 years old and are quite sandy (worn). Do you suggest anything for sealing, undercoating and topcoat for a terracotta coloured roof?

A. Weathered concrete/terracotta tile roofs are typically infested with mould, widespread lichen and moss growth. Removal of these are critical to achieving a successful long term decorative paint system.

Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 3: Treat areas of moss / lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label instructions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 4: Water blast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to water-blast under the tiles. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes. Leave down pipes disconnected for the first few showers of rain to wash out surfactants from the top paint film.

The paint system is a full coat of Resene Sureseal and then two coats of Resene Summit Roof.

Q. We are in the process of painting our house. We have a COLORSTEEL® roof which is 15 years old, the screw heads are rusty, how do we treat these before painting? Or do we need to replace the screws with new ones before painting?

A. Rusty screws are a tricky one. Typically when we talk about painting over previously corroded surfaces we need the surface to be thoroughly prepared prior i.e. all corrosion removed before priming. With screws etc it's almost impossible to prep them sufficiently.

Often roofers or roof painters will just replace them as it's actually a lot quicker and easier to do this.

If you were to leave in place you'd want to ensure that all loose rust etc is removed as best you can. Then prime with two coats of Resene GP Metal Primer before painting your roof.

Q. I need to paint an old (+/- 30yr old) decramastic type (sheet metal with grit) tiled roof. The grit coating has worn off in many places and a lot of bare metal is showing through. What is the best primer to use before coating with Resene Lumbersider?

A. Remove any loose corrosion using 3M Rust and Paint Removal Disc and prime bare metal with two coats of Resene Galvo-Prime before topcoating.

Q. I have a 28 year old COLORSTEEL® roof with puzzling blistering on the third from right flat part of profile. This is only on a few sheets all the rest are ok. However advice on how to treat this, also rest of roof and which of your products to use would be appreciated to paint whole roof. The roof is original COLORSTEEL® Karaka, never been painted or chemically cleaned and we are many miles from the ocean. There is no overhanging vegetation, and the area affected us well away from our chimney.  The entire sheet is affected.

A. It is unusual to see only a few sheets affected on a particular location. Given the age of the roof the original coating system has performed well. Is there any fallout form a chimney that may explain the blistering or over hanging vegetation?

The zinc present on galvanised or Zincalume roofing is sacrificial, the zinc oxidises and this electro-chemical reaction protects the underlying in steel from corrosion. White rust is the by-product of the zinc reacting with the atmosphere eventually the zinc is totally consumed and then the steel begins to rust and red rusting is seen. The rate of reaction is determined by the atmospheric conditions and salt that falls onto the roofing.

While the white material you see on the one roof section may well be white corrosion it is not usually confined to such a well-defined section of the roofing.

Suggest that you look to undertake a total strip of the affected section to see if there is under film corrosion present. If this is the case then you can apply a paint system to extend the life of the base material.

White rust forms when zinc is in an environment with hydrogen and oxygen. Most frequently, it occurs when a freshly galvanised material is placed into contact with water. White rust is especially likely to form on newly galvanised material. This is because the new zinc coating has not yet had the chance to form the stable oxides, and the hydrogen and the oxygen bond with the pure zinc which forms zinc hydroxide. White rust can be common on galvanised sheet that is being stored, as condensation can become trapped between the individual sheets, leading to the formation of white rust.

Scrub down using Resene Paint Prep and Housewash diluted and used to label directions. Rinse clean or hose down with fresh water ensuring all salts are also removed.    

All paint that is flaking or unsound must be removed by using mechanical methods (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblasting taking care not to damage either the substrate or the surrounding areas.

For the stripped section, after stripping remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc,  taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note:  The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are sound and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer.

Prime bare substrates with two coats of Resene GP Metal Primer then apply two coats of Resene Summit Roof.

Q. What is the best Resene paint to paint my gutters/spouting? The spouting has already had a coat of paint 7 years ago but I'm unsure of whether this was water or oil-based paint. I'm looking at having a copper type look so if you can recommend something it would be appreciated.

A. As long as the painted guttering surfaces are clean and the existing paint system sound we would normally recommend Resene Sonyx 101 as the topcoat.

Q. I am preparing to paint my garage roof and the corrugated iron has patches of surface rust so I want to know what product to use before painting. Do I need to use Resene Rust-Arrest and should I treat the whole roof or just the patches?

A. Wash down using Resene Roof and Metal Wash diluted and used to label directions. Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound this must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc,  taking care not to damage either the substrate or the surrounding areas.

Spot prime prepared areas of corrosion using Resene GP Metal Primer then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof.

Q. My powder coated aluminium roof was repainted in the past due to colour variations. It now has large areas of blistering substrate that looks like aluminium - is this possible?

If this is correct an etch primer will cause the existing acrylic system to curl at the edges of the bare areas.  Can I use Resene Galvo-Prime as I know it has great adhesion properties?  It will be repainted in an off white colour.

A. It could be aluminium (if you use a magnet you can confirm if it is aluminium) as it is often powder coated, but however cannot say with 100% accuracy. High pressure water blast (say 5000 psi) to remove loose paint, feather back edges where the paint has been removed then use Resene Galvo One as the primer, sorry not Resene Galvo-Prime.  Then topcoat.

Q. We are getting a new COLORBOND® roof and gutters. I need to paint my steel fascia what prep/paint should I use?

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label directions. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label directions. Rinse clean or hose down with fresh water ensuring all salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc,  taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note:  The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are sound and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer.

Spot prime areas of prepared carrion and bare metal with Resene GP Metal Primer then apply two coats of Resene Summit Roof.

Q. I've been asked to paint a yellow warning line near the edge of the roof of a building. I'm thinking Resene Summit Roof or Resene Hi-Glo. The gloss paints are harder wearing, right? But will it look funny on a faded old roof?

A. You will have to use Resene Hi-Glo as the colour Safety Yellow is not available in Resene Summit Roof. Given that it is a safety marking requirement, I would not be that worried about gloss level difference with the existing roof paint.

Q. I have rust around the lead head nails on my roof. What is best practice to repair this? There is light rust showing in odd spots in the middle of the sheet also. Replacing the iron would be too expensive.

A. Wash down using Resene Roof and Metal Wash diluted and used to label directions. Remove loose corrosion/rust deposit using a 3M Rust and Paint Removal Disc and spot prime these areas with two coats of Resene GP Metal Primer before topcoating.

Q. What is the best way to deal with surface rust on galvanised nails, on a COLORSTEEL® roof (20 years old), prior to painting in a seaside location?

A. Wash down using Resene Roof and Metal Wash diluted and used to label instructions. Remove all areas of white corrosion material and as much red rust as is practicable. All paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, taking care not to damage either the substrate or the surrounding areas.

Prime the prepared rusted nails with two coats of Resene GP Metal Primer and then topcoat with Resene Summit Roof.

Q. Can you tell me if downpipes should be removed, if roof water is supplying a water tank, prior to using Resene Moss & Mould Killer?

A. If the active in the Resene Moss & Mould Killer completely reacts then the reaction product is sodium chloride, common salt. However, in practice this does not always occur so to be safe, disconnect down pipes for all stages of preparation and painting, allowing the rain shower washing after completion of painting before reconnection.

Q. We built our house 13 years ago and it has a Resene Ironsand roof. We first painted our barge boards. Unfortunately this failed and split in the first few years so we started over. Cleaned, prepped and redid it with another product but that only lasted a year as well. Start over again, and did it in another product to no avail. It happened again.

Recently I approached a roofing company to see if he could redo the barge boards in COLORSTEEL®. He said he had had the same issue with his house and he redid his in Resene CoolColour and that worked!

So my question is, given we haven't touched the barge boards for a number of years. What should be my next steps in terms of preparation, gap filling, priming/undercoating before repainting in Resene CoolColour paint?

A. A Resene CoolColour™ topcoat will not render the painted surface cool to touch but the CoolColour version will reflect more heat than the same colour made on non-cool technology.

Dark colours may cause the rapid drying of damp timber with the ensuing danger of warping, though this effect will be lessened when a CoolColour is selected in place of a standard colour. I recommend a total strip back to bare timber, thorough sand and then apply two coats of Resene Quick Dry and finish with two coats of Resene Sonyx 101 CoolColour Ironsand.

This system will give the best chance of achieving a better long term option than your previous systems.

Q. If painting a new COLORSTEEL® roof using Resene Summit Roof paint, do you need to prime it first?

A. Yes, prepare and apply Resene Pre-Coated Steel Primer then the Resene Summit Roof paint.

Q. I would like to paint my house. I have a concrete tile roof (stripped bare) and fibrolite weatherboards that are currently painted.
What paint products do you recommend for my roof, do I need to seal the tiles prior to topcoat? I have cleaned it and it's pretty clean but raw concrete, almost all original paint is gone.

A. Step 1: Rake out all joints and tile over laps to remove accumulated debris. Remove large clumps of moss using a scraper.

Step 2: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 3: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label instructions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 4: Waterblast at the maximum pressure that will not damage tiles to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Care is needed not to waterblast under the tiles. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes.

Apply a saturation coat of Resene Sureseal and then two coats of Resene Summit Roof.

Q. Can Roof Summit be used on iron roofs as well?

A. Yes, as long as any bare metal areas are primed with Resene Galvo One.

Q. I am painting an iron roof that has some rust spots on it - can you please recommend how best to prepare/treatment required?

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label directions. For heavy infestations more applications may be needed.

Scrub down using Resene Paint Prep and Housewash diluted and used to label directions. Rinse clean or hose down with fresh water ensuring all salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc,  taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Q. I am looking for a white paint suitable for applying to a textured fibreglass surface of approximately 15sqm that is part of a roof and open to all weather. Ideally we would like something which resists lichen growth as that has been a problem with the current paint. The finish can be anything from matt to gloss, but a semi-gloss or satin would probably be most aesthetically pleasing.

A. There are no additives that can be added to a paint to control lichen growth on a painted surface. The easiest way is to spray the roof with Resene Deep Clean diluted and used to label instructions at the beginning of spring and autumn and then leave nature to do the hard work.

Q. I've just painted my roof in Resene Summit Roof paint semi-gloss but I now want more of a low sheen finish because the roof is old and it shows the imperfections.  Can I put another product like Resene Lumbersider over the top or what other options do I have?

A. If you can I would wait for 6 months before making any decision on this matter, this will give the new paint time to settle down and undergo a degree of weathering.

Roof paints need to be as durable as possible and the time to chalking, breakdown of the paint surface is a function of gloss, the lower the gloss the sooner the onset of surface chalking will occur.

Q. We want to repaint our COLORSTEEL® roof and would like to enquire which paint is recommended. As we are on tank water, the roof is where our water is collected and would like to know that the paint used is the healthiest choice.

A. Wash down using Resene Paint Prep and Housewash diluted and used to label directions. Apply a full coat of Resene Galvo One and then two coats of Resene Summit Roof. Note the instructions on the label for requirements where rain water is collected for drinking.

Q. I'm arranging to have my metal roof repainted. It is showing signs of rust, not too bad but needs attention. I am planning to have it water blasted, then painted. The roof is long run galvanised metal, about 45 years old. Single plane almost flat. It has never been painted. It is rusting mainly along the raised edges but also along the flat valleys of the profile. Rust (brown) is starting to need attention. My concern is to stop the progress of, and cover, the rust. The colour is not important, it is hardly seen.

A. We recommend Resene Alumastic.

Q. I'm painting an old villa with a corrugated iron roof. It's in bad condition with blistering paint all over and some rust areas, paint is also flaking off after I've waterblasted. It would take forever to try and scrape and sand it back so I was thinking of getting it soda or vapour blasted. What do you recommend?

A. The following is our standard prep for metal roofing; if any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label directions. For heavy infestations, more applications may be needed. 

Scrub down using Resene Roof and Metal Wash diluted and used to label directions. Rinse clean or hose down with fresh water ensuring all salts are also removed.

All paint that is flaking or unsound must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc, taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound, must be removed by using mechanical methods e.g. 3M Rust and Paint Removal Disc,  taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place, the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are sound and immediately spot prime all areas of corrosion and any other bare metal with a full coat of the specified primer.

After stripping and preparing corroded areas as above, spot prime areas of prepared corrosion with Resene GP Metal Primer then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit.

Q. We have had the moss waterblasted off the corrugated roof that we wish to paint but think we may need to treat the roof so it doesn't grow back? What are your suggestions?

A. Waterblasting alone does not kill residual moss spores.  I suggest that you treat the roof with Resene Moss & Mould Killer diluted and used to label directions prior to painting. Moss usually grows where damp shaded conditions exist for a prolonged time.

After painting, we suggest an annual application (spring or autumn) of Resene Deep Clean to give ongoing control of moss growth.

I appreciate that this may not be an easy fix but it does work.

Q. I'm arranging to have my metal roof re-painted. It is showing signs of rust, not too bad but needs attention. I am planning to have it waterblasted, then primed and painted. The roof is long run galvanised metal, about 45 years old. It is single plane, almost flat, invisible fasteners, no nails and has never, ever been painted.

It is rusting mainly along the raised edges but also along the flat valleys of the profile and the rust (brown) is starting to need attention. The topcoat colour is not a priority, halting the rust is.

A. We recommend Resene Alumastic.

Q. I have a well weathered COLORSTEEL® roof. Can I paint Resene Summit Roof paint on direct, or do I need to put a coat of Resene Galvo One primer on first?

A. For best results, scrub down using Resene Roof and Metal Wash diluted and used to label directions then apply a full coat of Resene Galvo One before applying the two coats of Resene Summit Roof.

Q. Can I paint polycarbonate plastic conservatory roof panels? The paint will of course need to be long term (5 year)?

A. Any Resene exterior waterborne paint i.e. Resene Sonyx 101 will achieve very good adhesion to polycarbonate. Ensure two coats are applied and the polycarbonate is clean.

Q. I am about to start painting a 45 degree corrugated steel roof. It has been painted before, last time by spray painting with a waterbased paint. That would have been about 10 years ago. The deterioration is mainly that the coating is just wearing thin, with only a very few places where there is peeling. On the south side there is lichen infestation especially near the lower edge, and that is my main concern. I want to do a good job and will probably be spending a couple of years doing this in my spare time, moving a scaffolding frame progressively around the house, completing a section at a time.

I need to be able to deal with the lichen as completely as possible in one shot at each set up, although there is scope I suppose for spraying ahead with a wand/boom.

Is it feasible to spray 2% sodium hypochlorite and then in a fairly short timeframe, waterblast effectively?

My procedure then would be one coat of Resene Galvo One and two coats of one of the Resene CoolColour range acrylic roof paints.

A. You can spot treat the lichen with concentrated Resene Moss & Mould Killer but we still suggest waiting a couple of weeks before waterblasting, to allow for loosening of the lichen attachment.

Q. I have a 40 year old Decramastic roof that needs painting. I notice you list three different undercoats for either bare metal (Resene Galvo One), bitumen coating (Resene Membrane Primer), and a waterbased general metal primer (Resene Galvo-Prime). Can I use the waterbased primer (Resene Galvo-Prime) as an adequate undercoat for the whole roof? I intend to use a spray applicator, or do I have to try and sort out the various conditions of the tiles and brush on different undercoats accordingly?

A. Resene Galvo-Prime is the only one of the primer set we use for priming Decramastic roofing when repainting. There has recently been a report from AHI Roofing that Decramastic and Harvey Tile roofing made prior to the mid-eighties may contain asbestos in the bitumen base. For this reason, we do not support waterblasting of these roofs.

Treat lichen/algae/mould by treating with Resene Deep Clean diluted and used to label instructions. Ensure when washing down that downpipes are disconnected and a filter placed over the exit pipe to collect any dislodged bitumen and chip. Seal these in a bag for disposal at an approved site.

Q. I have an old, partially painted corrugated asbestos roof. I have brushed Resene Moss & Mould Killer on the bare patches and where there is moss. What primer and paint should I use?

A. Following a soft rinse down to remove loose surface contamination, spot prime bare areas with two coats of Resene Sureseal and two coats of Resene Summit Roof to all areas.

Q. We have a COLORSTEEL® roof that is about 15 years old. It is in reasonable condition but has some lichen on it. Is it normal to re-paint this kind of roof? I was going to get it cleaned and see how it looks then. Does one get any reasonable extended life if it is painted?

A. Lichen will need to be treated and then removed; lichen can be difficult to kill. We suggest that the lichen is treated with Resene Deep Clean diluted and used to label instructions. Apply on a dull day to give the longest wet contact time with the lichen, if the infestation is heavy apply then re-apply the diluted solution a few hours after the first. Then leave the roof for at least 4 weeks and waterblast. This should result in removal of dead lichen residues and give a surface suitable for painting. Apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof colour.

This system is recommended as the surface condition is sound and there are no signs of corrosion.

Q. I am after a paint system for HardiPanel® compressed sheet to the ends of the gable roof. 

A. Our standard paint system for this substrate is to apply a primer coat of Resene Concrete Primer and finish with two coats of a Resene waterborne enamel such as Resene Sonyx 101.

Q. If we get our roof painted in a first anti-sun protecting coat and the weather or the season intervenes and the next coat is delayed, suppose we get a pollen deluge or say a lot of bird droppings (we are very near a pine plantation and reserve).

How long does it take for a coat to cure and be ready for a good waterblast before the next coat? And, is there any chance that such a waterblast could threaten the durability of the first coat and its warranty?

A. The paint should be touch dry after three hours post application, but will take at least a week to fully harden to final film hardness. The other factor is how hot the roof will get (colour determined), the roof paint can be touch dry but when the roof coating warms up this will certainly result in a greater chance of pollen deposits becoming fixed to the paint. I would allow at least two weeks before trying to waterblast and then avoid high blast pressures. Waterblasting should not affect the initial coat unless the underling paint system has poor adhesion.

Q. My garage roof has got rust even though it was originally galvanised steel. It was never painted to start with. I want to stop the rust and paint it. Can you tell me what I should use? I was thinking of thinking of starting with Resene Roof and Metal Wash followed by Resene Rust-Arrest, then Resene Galvo-One and finally a topcoat.

Would this be sufficient for this job bearing in mind that the original galvanising has worn off quite a bit and the steel is now rusting in places.

A. Resene Rust-Arrest is only suitable for application to red rusted areas, this excludes white rust or an area where some zinc remains. The primer to use would be Resene GP Metal Primer, two coats. You will need to wash down using Resene Roof and Metal Wash and then remove all loosely adherent rust before priming. If there is extensive red corrosion then painting may not give you an extended time to the roof life and maybe you should consider re-roofing for a long term solution.

Q. Can we use Lumbersider on an iron roof?

A. Resene Lumbersider can be applied to any appropriately primed substrate, including roofing. Please refer to the Resene Summit Roof data sheet for priming requirements.

If you are planning to use a dark colour, our recommendation is to apply the CoolColour™ version of the colour. The Resene CoolColour topcoat will not render the painted surface cool to touch but the Resene CoolColour version will reflect more heat than the same colour, made on non-cool technology. Lower gloss level finishes applied to roofing will undergo surface chalking more quickly than a higher gloss level paint of the same type. The Resene CoolColour will help with this but not prevent the onset of chalking. The rate of chalking is dependent upon exposure conditions and elevation, with the northerly elevations always showing the first sign of chalking.

Q. I have a fibreglass roof. Can I clean it and topcoat in Resene Sonyx 101?

A. Epoxy primers such as Resene Armourcote 221 will achieve the best adhesion to clean and sound fiberglass, the primer is best topcoated with a two pack polyurethane such as Resene Uracryl 402 for a semi-gloss finish.

Q. I’ve got a galvanised roof to paint which is two months old and located in Rotorua. What paint products would be suitable for this environment?

A. Wash down with  Resene Roof and Metal Wash diluted and used to label directions, then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof.

Q. COLORSTEEL® advise they do not apply any colours at their factory other than COLORSTEEL® colours. How do I get Resene Sword applied to a new build roof as a factory paint application? Hand painting is an unsatisfactory option.

A. Repainting of new COLORSTEEL® requires an extended period of weathering before the coloured cladding can be painted. If you are going to paint, then why not start with Zincalume? The painting of Zincalume will require a prime coat and then topcoating. If the cladding profile is in already in place, this is possible. If the plan is to paint then install, there will be a requirement for site touch up, as there will inevitably be installation damage.

Q. The conservatory attached to the house has a butyl rubber roof covering. The butyl is shedding a damp black sooty residue, down over the glass and aluminium. Do you have you a sealer suitable to cover the butyl to prevent this happening?

A. Scrub down using Resene and Prep and Housewash, diluted and used to label then apply a coat of Resene Membrane Primer and finish with two coats of Resene Lumbersider.

Use the Resene CoolColour™ version of the topcoat colour if selecting a dark colour for the topcoat. The CoolColour topcoat will not render the painted surface cool to touch but the CoolColour version will reflect more heat than the same colour made on non-cool technology.

Q. Can I use your roof paint (permanent green) on outside wooden windowsills? They have been sealer undercoated.

A. Yes, as long as the substrate has been appropriately prepared and primed.

Q. What is your recommended paint system for a decramastic roof? The roof has already been waterblasted at 3000PSI and mould killer sprayed. No rust is present but there are some bare steel patches where grit has worn off.

A. We recommend a full coat of Resene Galvo-Prime and then two coats of Resene Summit Roof (use the Resene CoolColour™ version of the colour if a dark colour is required).

We have no system to restore the original texture to a Decramastic roof.

Q. I have been up on my roof and see the galvanised surface has worn off the roof and the reaction to the sea air has caused red rusty coloured marks everywhere. It is smooth to touch not gritty, it feels like chalky paint. The roof underneath looks in good condition and it is not rusted through any holes. I wish to do this myself as it is a flat pitch roof. I went into Resene yesterday and bought some Resene Roof and Metal Wash (small one to try it) on a patch. Is this what I should be doing or should I sand and treat with Resene Galvo One?

A. A definite yes to a wash down using Resene Roof and Metal Wash. Remove all areas of white corrosion material and as much red rust as is practicable using mechanical methods e.g. 3M Rust and Paint Removal Disc, taking care not to damage either the substrate or the surrounding areas. Spot prime prepared areas of rusting with Resene ArmourZinc 110 to achieve a dry film thickness of 75 microns, then a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof.

Q. I want to paint my corrugated iron roof. It is in fairly good condition, except for some areas where a bit of rust is showing through. After waterblasting and cleaning the roof first, is there a paint that I can put over the rust that will seal it? Then do I go straight over that, with the roof paint and what is the best roof paint to use?

A. Ensure all loose rust is removed using a 3M Rust and Paint Removal Disc, then spot prime corroded areas with Resene GP Metal Primer. If close to the sea, apply two coats of the primer then finish with two coats of Resene Summit Roof.

Q. We have decided to paint our corrugated tin house roof in Resene Nullarbor. The sales assistant said we could have this colour in a roof-suitable paint. She also said the same paint would be fine to paint the wooden fascia/barge boards. Believing in a do it once do it right mantra, my question would be 'is there a better choice of paint type (same colour) for the wooden components?

A. Resene Summit Roof can be used as the topcoat system for other substrates, as long as they are primed with the appropriate priming system.

Q. We are placing a bitumen rubber waterproofing membrane on top of an older black butynol roof. We wish to use Resene X-200 paint to match the walls on top of this membrane. Is it acceptable to paint over the bitumen with the Resene X-200?

A. Apply a primer coat of Resene Membrane Primer then the Resene X-200.

Q. I was wondering if you had any advice, or a product that could be used to rejuvenate an old Decramastic roof?

A. Decramastic roofing tiles, also known as Decrabond or pressed metal tiles were widely used in New Zealand during the 1970s and 1980s. Made of galvanised steel with a bitumen overlay, the tiles were known for being lightweight and easily installed. Upon weathering the tiles will lose chip texture erosion of the bitumen base back to base metal which at the extreme will present with corrosion.

This specification will restore colour but not the original chip texture.

Step 1: Spot treat areas of heavy lichen infestation with Resene Moss & Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding to Step 3.

Step 2: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label instructions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 3: Wash down with water to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Waterblasting is not recommended as this will result in the dislodgement of the chip. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes.

Step 4: All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblasting taking care not to damage either the substrate or the surrounding areas. Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblasting taking care not to damage either the substrate or the surrounding areas. Where under-film corrosion is taking place the existing paint must first be removed and remove corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish. It is strongly recommended, that any badly rusted sections of galvanised steel be replaced.

Spot prime any bare metal or bitumen with Resene Galvo-Prime and apply two coats of Resene Summit Roof. Where there is red rusting; apply two coats of Resene Galvo-Prime to the prepared areas.

Q. I have painted our roof with Resene All Black CoolColour. I still have some left is it alright to paint the Hardiplank® on the walls with it? They have previously been painted.

A. In theory yes, but application of a very dark colour over an existing paint system can stress the existing paint and cause delamination which is not the fault of the new paint.

The application of the Resene CoolColour™ version of the colour over a white basecoat such as Resene Quick Dry will reduce but not eliminate the potential for delamination.

Q. How and where should I store unused roof paint for later use?

A. Store in a cool area that is not subject to much temperature variation. If a can has been opened then despite correct storage conditions there may be bacterial growth in the can, the bacteria can be introduced from the air or application equipment.

Q. I am looking for paint, suitable to paint over a Butynol style roof.

A. Scrub the Butynol down with Resene Paint Prep and Housewash diluted and used to label directions. Apply a coat of Resene Membrane Primer and two coats of Resene Lumbersider or Resene Sonyx 101, the latter topcoat will have a longer time till the onset of surface chalking. The system is suitable for roofing but not for guttering and will not restore a failure in the Butynol to achieve a watertight membrane.

Q. I have a flat roofed house by the sea. The roof is covered in a black bituminous torch-on product which is in good condition. Several years ago the roof was painted with some type of aluminium paint. This paint is generally in good condition but there are patches where is has powdered off to expose the torch-on. I wish to clean and then repaint the entire roof. Please tell what primer/undercoat and top coat product I am best to use which adheres to both the black torch-on and the remaining aluminium paint. I want the new topcoat to again be an aluminium colour.

A. The aluminium paint is more than likely similar to Resene Silvalusta. These finishes can only be over coated with the same paint type and can't be over coated with standard waterborne decorative paints.

Q. I have a very old and rusty roof and want to make it look good as we are selling up.

A. Apply a full coat of Resene Galvo-Prime metal primer and then finish with two coats of Resene Summit Roof.

Q. We have a tin roof on a garage that has a lot of rust. How are we best to treat this? It’s just surface rust so does it need wire brushing and then coating with a product?

A. The standard system would be to wash down using Resene Roof and Metal Wash diluted and used to label directions, then spot prime prepared areas of red rust, with two coats of Resene Galvo-Prime and if the rest of the roof is weathered bare galvanising, apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof.

Q. I'm planning to paint the roof on my rural property. My water supply is rainwater from the roof. Do you carry a roof paint that is non-toxic and suitable for this purpose?

A. We recommend Resene Summit Roof.

Q. Our iron roof was repainted using Resene paint just over a year ago. Since then, bubbles have developed in the paint across the surface. Slicing open some of the bubbles reveal the bare metal, indicating that the old original paint has failed and has been pulled away from the iron by the tension of the new coat. What would be the correct procedure now to remove the bubbled paint?

A. The easiest first step is to high pressure waterblast.

Q. We have three Decramastic roofs we want to paint. Can you advise on the best way to do this? There are small amounts of lichen and red surface rust.

A. Remove all loose red rust, using a 3M Rust and Paint Removal Disc, treat lichen using Resene Moss & Mould Killer. After application of Resene Moss & Mould Killer, leave for two weeks to allow for the lichen to become detached. Resene Summit Roof is the recommended topcoat (two coats). We cannot offer any system to restore the chip profile.

Q. Is Resene Hawkes Blue, suitable as a roof colour?

A. The colour is an off white. If using as a roof colour I would apply a coat of Resene Clearcoat UVS over the base paint colour.

Q. We are looking at repainting our 20 year old COLORBOND Karaka roof in New Plymouth (4km from coast). The paint is fading, especially on the northern side. Do we need to apply Resene Galvo-Prime to the whole roof? If using Resene Summit Roof Karaka CoolColour - do we need two coats?

A. There may be delamination on some flashing areas. Scrub down using Resene Roof and Metal Wash and remove failing paint by preparing with a 3M Rust and Paint Removal Disc. Spot prime any bare substrate with Resene Galvo One, and then apply two coats of Resene Summit CoolColour™ Karaka formulation. Application of a full coat of Resene Galvo-Prime will give the maximum heat reflection for the CoolColour system.

To extend the time to next maintenance, you can apply a coat of Resene Clearcoat UVS over the Karaka base colour. This will extend both the life and colour of the colour but it will give a gloss finish.

Q. We need to repaint the COLORSTEEL roof of our bach, but the coating is delaminating. What is your recommended method, to prepare this roof so the new paint job will last?

A. High pressure waterblast to remove loose paint, and then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof CoolColour™.

Q. I want to repaint a COLORBOND® roof. The original metal doesn't appear to be genuine - not sure what the original colour base was (acrylic or oil) as it has faded and peeled whereas the caps/ridges (likely genuine) have held fast the original colour. The plan is to clean, undercoat and top coat x 2. What products should I use for all three steps?

A. High pressure waterblast to remove all loose paint, then scrub down with Resene Roof and Metal Wash diluted and used to label directions. Spot prime bare metal with Resene Galvo One and finish with two coats of Resene Summit Roof. If you choose a dark colour we recommend using the Resene CoolColour™ version of the colour to give increased heat reflection compared to the same colour made using non-cool technology. A CoolColour will not render the painted surface cool to touch but it will be cooler than the same colour made using non-cool technology.

Q. I have had my concrete roof tiles waterblasted. Quite a bit of the glazing has come off to expose the concrete. I wish to repaint eventually but I understand they will need sealing first? What product/products should I use?

A. Use Resene Sureseal for sealing bare concrete priming.

Q. We have a stone chip coating, steel tile roof. No rust, but it has started to fade and I don’t think it has ever been painted.

Can you please give advice as to what products you would recommend? I'm guessing standard, steel roof paint will not be sufficient, due to the stone chip coating.

The stone chip is embedded in a bitumen base, but some has more stone chip than others.

A. If this is the standard of the existing roof system over the whole roof then clean down with Resene Roof and Metal Wash diluted and used to label directions. Then apply a full coat of Resene Galvo-Prime and two coats of Resene Summit Roof in the CoolColour™ version of the selected colour if available.

Q. I am repainting a corrugated iron roof that has some red rust starting to show through. I am getting mixed messages about whether to use a rust converter or not.

A. Resene does not recommend using rust conversion primers for treating areas of rust. We have limited confidence in rust convertors giving long term corrosion control despite the product description. Clean back any light corrosion with a nylon Scotch rite scouring pad or similar. For heavier red rust clean back by sanding with 80 grit sandpaper or a 3M rust and paint disc. This should be confined to the red rusting areas only. This will avoid damaging the protective galvanised layer, which will simply lead to more rusting. Apply a coat of Resene GP Metal Primer. Areas showing significant red rusting will require an additional coat of Resene GP Metal Primer. You could use Resene Rust-Arrest on the red rust areas, but it does not adhere well to the adjacent galvanised surfaces as it reacts with the zinc.

Q. I have a 20 year old butynol roof which needs painting. What is the best solution?

A. You can paint butynol but this is only to protect the material from weathering. If there are tears or breaks in the butynol layer we cannot offer a paint system that will give waterproofing. In the event the latter does not apply the following can be undertaken: wash down with Resene Paint Prep and Housewash and prime with Resene Membrane Roofing Primer then apply two coats of Resene Summit Roof. It’s best to avoid dark colours but if you choose a dark colour then use the Resene CoolColour™ formulation of the colour which will give more heat reflection from the painted surface than the same colour made using conventional colourants.

Q. Eleven years ago I put a corrugated iron roof on a shed. It has overhanging vegetation. I now want to paint it. Should I etch it with something, or can I paint it with one of your paints. And if so, what type of paint should I use?

A. You will need to cut back the overhanging vegetation, then clean the roof down using Resene Roof and Metal Wash diluted, and used to label/data sheet directions. If, after removal of the overhanging vegetation and brushing other debris off, there are signs of algae/mould/lichen then treat with Resene Moss & Mould Killer and again diluted and used to datasheet/label directions, and then clean down using the Resene Roof and Metal Wash.

Treat the ply with the Resene Moss & Mould Killer diluted and used to datasheet/label directions.

Prime the roof with Resene Galvo One, and then apply two coats of Resene Summit Roof paint. Prime the ply with Resene Wood Primer and then apply two coats of Resene Summit Roof.

Q. We have a Decramastic tile roof and were wondering if it can be painted. We are a rural property and collect rainwater from the roof for our household use.

A. Decramastic roofing tiles, also known as Decrabond or pressed metal tiles were widely used in New Zealand during the 1970s and 1980s. Made of galvanised steel with a bitumen overlay, the tiles were known for being lightweight and easily installed. Upon weathering the tiles will lose chip texture erosion of the bitumen base back to base metal which at the extreme will present with corrosion.

This specification will restore colour but not the original chip texture.

Step 1: Spot treat areas of heavy lichen infestation with Resene Moss and Mould Killer diluted 1:1 with water and leave for 48 hours before proceeding.

Step 2: Treat areas of moss/lichen infestation a few weeks prior to the commencement of painting with a saturation coat of Resene Deep Clean diluted and used to label instructions. Resene Deep Clean is a slow release bio kill agent. Resene Deep Clean is best applied under overcast conditions to maximise wetting time.

Step 3: Wash down with water to remove all dirt, grease, moss and mould residue, dust, and other contaminants. Waterblasting is not recommended as this will result in the dislodgement of chip. Allow the surface to dry thoroughly. Resene recommend that downpipes are disconnected during this process and that gutters are thoroughly cleaned out before reconnecting downpipes.

Step 4: All paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods, (3M Rust and Paint Removal Disc), chemical stripper or high pressure water-blasting taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed and then remove corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish. It is strongly recommended that any badly rusted sections of galvanised steel be replaced.

Prime any bare metal or bitumen areas with Resene Galvo-Prime then apply two coats of Resene Summit Roof.

Q. We are using a contractor to paint our roof using Resene Summit Roof paint (Bright Charcoal). This is the same paint as the roof was painted in approx. 6 years ago. The north side of the roof has suffered extensive blistering and the contractor is saying that it was poor preparation of the original paint. They are tearing very large layers of paint from the roof and it is mostly back to base metal. Are you able to advise if this could be poor application 6 years ago or whether it is more likely the new application? There was no blistering before the roof was newly painted last week.

A. If it is peeled back to bare substrate, then the adhesion issue is with the first coat of paint that was originally applied. Successive application of paint layers will have placed stress on the adhesion of the first coat and when the stress exceeds the adhesion strength of the paint then it will delaminate/blister. It can be difficult to visually see this issue when repainting unless there is an existing sign of blistering or lifting of the existing paint.

Q. I wish to take advantage of your sale and purchase my roof paint now. Is it OK to store it until next summer? Also I am repainting a COLORSTEEL® roof that has lost 90% of its colour. What primer should I use?

A. If the paint is stored in a cool well ventilated area it should be fine until summer; give the contents a thorough stir before using. After cleaning to remove surface chalk apply a full coat of Resene Galvo One.

Q. Our old house has an extension Kliplok roof (5 x 11m) about 45 years old. Rust has started on the roof and Lysaght recommended a primer then acrylic.

A. If it has taken this long for corrosion to appear, the galvanising has performed very well along with what I assume is a relatively low corrosivity exposure zone. In the situation you describe, we would normally specify Resene Alumastic surface tolerant epoxy applied to achieve a dry film thickness of 175 microns.

Q. I am preparing a spec for a renovation project with an existing painted steel corrugated roof in various states of repair. I believe the best option for this situation is either Resene Hi-Glo or Resene Hi-Glo CoolColour. The proposed colour has not been confirmed yet but will likely be dark. Is it possible to use the standard Resene Hi-Glo with a darker colour?

A. There is no reason why you cannot use Resene Hi Glo in either the non-cool or CoolColour™ version of the colour. There will be a greater heat reflectance with the CoolColour version of any colour. In principle given that the CoolColour will reflect more heat will mean an extension in the life of the paint before recoating is required. This extension will vary depending on variations in roof profiles and exposure conditions.

Q. My prepainted, galvanised patio roof support structure needs repainting desperately. What product and process do you suggest I use?

A. You will have to wash down the support structure using Resene Roof and Metal Wash diluted and used to label directions then remove all of the existing paint. Then apply a coat of Resene ArmourZinc 120, two coats of Resene Armourcote 221 and finish with two coats of Resene Uracryl 403.

Q. I am going to paint my iron roof that has a few surface rust spots. What product do I need to kill this rust and then what primer do I need and how many final coats do you suggest. Finally I have a five year old part of the roof that is COLORSTEEL® which is a different colour, what do I need to prep this to then paint the roof the same colour?

A. If any areas of moss or mould infestation exist then treat them with Resene Moss & Mould Killer diluted and used to label directions. For heavy infestations more applications may be needed. Scrub down using Resene Paint Prep and Housewash diluted used to label directions. Rinse clean or hose down with fresh water ensuring all salts are also removed. All paint that is flaking or unsound must be removed by using mechanical methods (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblasting taking care not to damage either the substrate or the surrounding areas.

Remove all areas of white corrosion material and as much red rust as is practicable and all paint that is flaking or unsound must be removed by using mechanical methods (3M Rust and Paint Removal Disc), chemical stripper or high pressure waterblasting taking care not to damage either the substrate or the surrounding areas.

Where under-film corrosion is taking place the existing paint must first be removed as above and remove under film corrosion products taking care not to damage sound zinc coated areas. All paint edges must be feathered to a smooth finish.

Note: The performance of the subsequent paint systems will be largely dependent on the thoroughness of this surface preparation stage.

Ensure all edges of damaged paint are sound and immediately spot prime all areas of corrosion and any other bare metal with a full coat of Resene GP Metal Primer before applying the topcoat system.

Q. When painting a COLORSTEEL® roof is it best to use a paint brush or a roller?

A. It actually makes little difference; a roller will be much quicker.

Q. I cleaned my concrete tile roof and treated it for mould. I painted one coat of paint with airless sprayer. The paint is bubbling and coming off. Why did this happen and what do I do now to fix it?

A. While a waterborne paint can be applied direct to concrete the condition of the concrete surface is critical to achieving adhesion. For aged roof concrete tiles we recommend cleaning to remove any biological growth such as mould/moss/algae and removal of any debris that has accumulated in joints or overlap areas. Then apply a seal coat of Resene Sureseal before applying two coats of Resene Summit Roof.

Can you cut a bubble and see if there is contamination (dirt/algae) of the back of the paint and what the condition of the surface is where the paint bubble was cut from? This will give an indication of possible failure mode.

Q. I need to paint my Decramastic roof. It has a few rust spots that I'm currently touching up. How should I paint it?

A. Ensure the roof is free from lichen/mould/algae; if required treat with Resene Moss & Mould Killer diluted and used to label directions. Spot treat heavy areas of lichen with undiluted Resene Moss & Mould Killer. Detachment of lichen may take 2-3 weeks and then wash down with Resene Roof and Metal Wash diluted and used to label directions. Ensure all lichen growth is washed off. Power tool clean areas of corrosion to remove lose corrosion deposits then spot prime these areas and any bare bitumen with two coats of Resene Galvo-Prime. Then finish with two coats of Resene Summit Roof. This system will restore a uniform colour but not the original texture of the chip surface.

Q. We have a flat butynol membrane roof with heat build-up in the cavity. We have been advised by a roof specialist to try ‘white coatings’ before attempting to install vents. Apparently this is a white paint with reflective additives. The roof already has one coat of white paint (but roof is dirty so not doing much). What product would you recommend and where can I get it?

A. There are white paints that claim to be more heat reflective white paints but these are not available here to the best of our knowledge. Standard white paint does have reflective properties and for your situation we would suggest a prime coat of Resene Membrane Primer and then three coats of Resene Sonyx 101 White (the more coats the better).

Q. I have a galvanised metal roof on the carport. It’s never been painted. Recently some surface rust appeared in places so I covered it with rust converter. I intend to paint it with a couple of coats of Resene Hi-Glo. Do I need to prime it first and, if so, what would you recommend?

A. We have limited confidence in rust convertors giving long term corrosion control despite the product description. Wash down using Resene Roof and Metal Wash diluted and used to label directions, Spot prime red rusted areas with Resene GP Metal Primer then apply a full coat of Resene Galvo One and then finish with the two coats of Resene Summit Roof paint.

Q. If we paint our roof with your Resene Summit Roof Paint in a CoolColour™, how long would it be before we need to repaint it again? We are thinking of using the Resene All Black colour so want to know what sort of life expectancy it has once it’s on the roof.

A. Difficult question to answer due to the colour, as adhesion should be no problem. The trigger for recoating will be surface chalking and this will vary with elevation, pitch and location. Typically roofs require on average repainting to restore aesthetics from 8 years on.

Q. The corrugated steel roof in question was put on the building in the early 1970s. There seems to have been no maintenance since then and the steel has extensive surface rust. Please recommend a primer that will effectively neutralise the corrosion and provide the best foundation for Resene acrylic finish coats.

A. Corrosion cannot be neutralised; in this situation the corrosion maybe have progressed beyond the pint of effective repair. However the following may well extend the life of the roof: scrub down with Resene Roof and Metal Wash diluted and used to label directions then waterblast.

If the areas of red rust are well defined (no intervening galvanising remaining) then prime these with a coat of Resene Rust-Arrest. If there are areas of remaining zinc then prime with Resene GP Metal Primer. Then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof.

Q. I painted our plaster home with Resene X-200 four years ago. The Butynol roof has produced run off stains in several places. Is there a product that will remove the stain?

A. The dark staining is from carbon used to colour the Butynol, and as the Butynol surface oxidises with weathering the carbon particles are released. Not aware of any easy way to remove this from an acrylic painted surface, the only long term solution is to paint the Butynol.

Q. I painted a roof (approx. 15 sq. m) in marginal conditions and some of the paint film has washed off overnight. What should I do before repainting in warmer weather please?

A. Wash down with Resene Roof and Metal Wash diluted and used to label directions.

Q. What undercoat and topcoats do you recommend for a tiled roof? Trying to avoid membranes if I can. My gun doesn't like them too well.

A. Achieving a totally clean roof is the key to a successful painting outcome. The roof must be cleaned to remove moss/lichen/algal growth and joints need to be raked out to remove accumulated material. Double treatment with Resene Moss & Mould Killer is the common way to deal with surface contamination. After treatment lichen will need to be left for a time to die and then detach. Then apply a saturation coat of Resene Sureseal and two coats of Resene Summit Roof.

Q. Just a question about your roof paint range. Are these paints compatible with an existing COLORSTEEL®-coated roof? We live in a sea-spray zone.

A. As long as the existing factory coating is sound and cleaned down then you can apply Resene Summit Roof paint.

Q. I live in Christchurch. Is it still OK to paint corrugated iron roof with Resene Summit roof paint in early autumn?

A. You can apply roof paint at any time of the year as long as the painting conditions are met.

Q. I am repainting my roof with Resene Ironsand CoolColour™. It is currently painted with a Resene white which is still in good order. Do I need to prime/undercoat the roof again prior to painting the Resene Ironsand? It seems unnecessary to me but am getting conflicting opinions.

A. If the existing coating is a waterborne roof paint and sound then all that should be needed is a scrub down with Resene Roof & Metal Wash following label directions before applying your paint.

Q. Approx. how much roof paint will I need for a house that is 120 square metres please? The roof is corrugated iron.

A. We usually add 40% to the floor area as an estimate of the roof area as this takes into account pitch and overhang. So this gives an estimated roof area of 168 sq. metres. Application of 2 coats each at 10 square metres per litre gives a total volume of 2 coats of approx. 34 litres. This is the best estimate we can give but it may well be under or over.

Q. I have a corrugated iron roof with old red paint on it. I want to remove the old paint and just have a grey coloured roof. What's the best way to remove the old paint - scraping, paint stripper? Do I need to repaint afterwards or can I just leave as is? I got a Stanley knife blade and scraped a section and it came off relatively easy but I didn't want to keep going if this method would make the iron rust.

A. If the paint adhesion is poor the high pressure waterblasting will be a quicker method to remove paint. The roof should be painted after removal of the red oxide paint as corrosion may well occur if left uncoated.

Q. Is it ok to add your bug repellent to CoolColour™ roof and wall paints?

A. It will have relatively short effectiveness if used in a roof coating.

Q. We have an iron roof which has not been painted previously. There are spots of minor rust around the nail holes. The nails have been removed and replaced with stainless steel screws but I now need to paint the whole roof. What primer should I use? The roof faces north.

A. Using a 3M Rust and Paint Removal Disc remove loose rust from areas showing rusting and immediately spot prime with Resene GP Metal Primer then apply a full coat of Resene Galvo One and finish with two coats of Resene Summit Roof CoolColour™. The CoolColour version of the colour will not be cool to touch but will reflect more heat than the same colour made using non cool pigments and give the maximum time to the onset of chalking. The time to the onset of chalking is always quicker for a north facing roof, and is also influenced by the roof pitch.

Q. We have a new butynol roof over a porch. The builder has waterblasted it but it's marked so he recommends painting it with a primer and two coats of acrylic topcoat. Is this a good idea? Also the guttering above this leaks but he doesn't seem too keen to fix the leak in the joins, so there are wet patches on the roof every day. The builder seems to think this is not a problem but we don't think painting a wet roof is advisable. Is it still advisable to paint the roof even though it's wet with puddles of dew each morning?

A. We do have a waterborne paint system for butynol. We recommend a coat of Resene Membrane Roofing Membrane and two coats of any Resene exterior waterborne topcoat paint. However if the roof is wet at the time of painting and remains wet during the drying then the paint system will be washed from the butynol. However once dry and cured the system is suitable for exterior exposure.

Q. How often should an iron roof be repainted? Also the outside walls which are a thin composite material?

A. In New Zealand the average repaint time for roofs is 8-10 years. Repainting should only be necessary to maintain aesthetics. Colour, roof pitch elevation and gloss of the roof paint can also alter these times. The same would apply to wall claddings. The north and western elevations always show signs of weathering sooner than the other two elevations.

Q. Is roof paint suitable for use on timber as well as the iron roof?

A. Most waterborne roof paints can be applied to appropriately primed timbers.

Q. Which roof paint (black) is your most popular and ties with Resene Pitch Black Woodsman stain? I'm getting my roof touched up and no-one knows what the existing paint colour is.

A. Resene Black is available in Resene Summit Roof Semi-Gloss. We would recommend using the Resene CoolColour™ version of the colour if painting a roof.

Q. I have just completed painting my roof with Resene Summit Roof paint satin exterior, colour Resene Helium. I intend to recoat it and have about 8 litres left. Being almost white it is not always easy to see the next coat as it is applied so I would like to tint it. I have about half a litre of Resene Hi-Glo gloss acrylic/miox exterior and being a nice deep blue (colour Resene Undercurrent) I was hoping to mix this in as my tint. I am therefore just checking to see this will be OK and not compromise the Resene Summit Roof paint.

A. Sorry but Resene Hi-Glo cannot be mixed with Resene Summit Satin Roof paint, although both are waterborne they are based on very different resin systems and exterior durability especially on a roof may be severely compromised.

Q. I am repainting a 30 year old corrugated iron roof last painted 11 years ago (beach property). Am proposing two coats of Resene Summit Roof. The iron is in good condition. Do I need to prime or will two coats of Resene Summit Roof suffice?

A. If there are no signs of corrosion or flaking paint on the painted roof then wash down with Resene Roof and Metal Wash following label instructions and apply two coats of Resene Summit Roof.

Q. I am painting the roof of my house which is quite old. The roof is in good condition with most of the paint being removed down to the galvanised surface with waterblasting. Is your Resene Summit Roof product suitable or should I use a primer?

A. Prime all bare galvanising with Resene Galvo-Prime before applying Resene Summit Roof Semi-Gloss.

Q. We have a Zincalume roof and the beams are exposed so we have no insulation. What do you suggest we can do to reduce the heat build up in the house? Should we paint it white? The roof is unseen from the road.

A. White is the best 'colour' to achieve heat reflection. While we have Resene CoolColour™ versions of a large range of colours including COLORSTEEL® colours these all have a total solar reflectance (TSR) value significantly below the TSR of white.

Q. When using Resene Summit Roof Semi-Gloss do you need to prime existing COLORSTEEL® or COLORBOND® with Resene Galvo One? Are there any special requirements applying Resene Summit Roof Semi-Gloss by spray?

A. If the existing COLORSTEEL® is sound and just chalked there is no need for priming. Priming is only required if the factory applied coating is showing signs of delamination.

From an equipment perspective the spray tip selection remains the same as Resene Summit Roof (satin) but now there is a requirement for a minimum spraying pressure and guidelines on when to use Resene Summit Roof Spray Additive. This is a new additive formulation and while extending open time the new additive has other functions which cannot be achieved by addition of Resene Hot Weather Additive. The addition rate of the dedicated spraying thinner is up to a maximum of 2% by volume, that is 200ml per 10 litre of paint (this must not be exceeded). The same requirements apply to application of Resene Summit Roof Metallic paints, Aluminium and MIOX bases.

Q. I'm painting a roof and assume CoolColour would be the most durable paint. What CoolColour colour matches the Karaka of your other paints?

A. Resene CoolColours do help reduce heat build-up. Another idea is to select a lighter colour, if that is an option. Lighter colours absorb less heat. Resene Karaka is available as a CoolColour. The CoolColour version of the colour uses different tinters to achieve the CoolColour effect but is matched to the same colour standard as the normal Karaka.

Q. I have a town house that has a lot of lichen on the corrugated iron roof. I want to paint it early next year. What is the best way to get rid of the lichen? Do I need to get someone other than a painter to take care of the problem? Can I waterblast the roof before or is it best done after the lichen has been treated?

A. Time is required to kill and allow lichen to detach. Given the delay until you will be painting I suggest that you find a professional company who will treat the roof to achieve lichen kill. The detachment after treatment with a lichen kill solution will take time and weathering with rainfall.

Q. I’m a builder and purchased a new home 5.5 years ago with a long-run iron Diamond/Brownbuilt type profile weathered COLORSTEEL® roof. Sadly the expansion and contraction creaking is really bad, even after 3-4 coats of the Resene Grey Friars we purchased - it hasn't had much affect. We also drilled the holes bigger, and introduced longer screws. The noise is definitely coming from the roof and maybe a little from the metal gutters. I’m very concerned as I thought this paint would reduce the noise.

A. Acrylic roof paints are not designed to reduce expansion or contraction of claddings, which arise from heating and cooling.Resene CoolColours, which do reflect more heat, may assist in reducing the temperate extremes but not to zero difference.

Q. We have purchased Resene Hi-Glo by mistake instead of Resene Summit Roof which we already have on our roof. Can Resene Hi-Glo go over Resene Summit Roof?

A. Yes Resene Hi-Glo can go over Resene Summit Roof (and vice versa). So you can use the Resene Hi-Glo you have already and then if you wanted to change to Resene Summit Roof you could do so at the next repaint. The difference between the two products is that Resene Hi-Glo is glossier and Resene Summit Roof is a satin finish and direct to substrate on some surfaces. However as you have a coated roof already, the direct to substrate feature is less relevant as the roof is already painted.

Q. I have a 1960s property with a Decramastic roof. The Decramastic chips are either weathered or over time have washed away leaving bare iron. Could the roof be restored with Resene Resitex elastomeric textured coating preceded with washing and priming with Resene Galvo-Prime? I would envisage applying Resene Resitex with a Hi-solid roller.

A. Yes you could carry out the system you suggested. Use Resene Galvo-Prime as the primer for bare metal or bitumen then apply Resene Resitex. However Resitex Standard is the only texture that can be roller applied.

Q. I have a small patch of rust on my COLORSTEEL® roofing (superficial, no holes). Just wondering what the best approach is to prevent it from spreading and what products you would recommend for painting?

A. Remove all corrosion back to a sound feathered edge using a 3M Rust and Paint Removal Disc then dust off and immediately spot prime the prepared arras with Resene GP Metal Primer, then overcoat with two coats of Resene Summit Roof.

Q. Is there a paint specification to repaint COLORSTEEL® roof flashings, which have lost some of their coatings? The site is exposed to sea spray conditions.

A. Scrub down with Resene Paint Prep and Housewash following label instructions to remove surface salts. Remove all loosely adhering paint back to a sound edge then spot prime bare substrate with Resene GP Metal Primer then apply three coats of Resene Summit Roof. Before painting each day wash down with fresh water and allow to dry before painting to reduce the chance of salt deposits between coats.

Q. Can Resene Hi-Glo be painted over Resene Summit Roof on an existing painted roof?

A. Resene Hi-Glo can go over Resene Summit Roof (and vice versa). The difference between the two products is that Resene Hi-Glo is glossier and Resene Summit Roof is a satin finish and direct to substrate on some surfaces. However as you have a coated roof already, the direct to substrate feature is less relevant as the roof is already painted.

Q. I've been asked to price a job, painting a not too old zincalume roof. The place is a warehouse/retail place and gets very hot inside. Now they have been told that by using "cool" paint it is going to make a difference inside - is that so? Are two top coats "cooler" and what would be the coolest colour? What about moss and mould on the roof - will they make it absorb more heat?

A. The best way to keep a roof cool is to paint it white. Whether that reduces the heat inside depends on the building - it can make a difference on some roofs by reducing the roof temperature which reduces the heat transference inside. In some areas, and depending on the roof, white may not be a colour that can be used. In that case you could consider a Resene CoolColour™ - this is colour made using special pigment technology - which will reflect more of the sun's heat than a standard version of the same colour. However white is always the most reflective colour and if it is purely reflectivity your client wants then they would be best to select white if they can. There is a white roofs movement that you can look up to find out more information on white roofs.

You can see more information on Resene CoolColour™ paint here.

We have a section on roofing on this website which covers off the priming requirements. As well as the prep and priming we recommend two full topcoats of Resene Summit Roof. Resene Hi-Glo is also an option if a higher gloss is required, but most people prefer the satin finish of Resene Summit Roof.

Moss and mould is definitely something to consider maintenance wise for any roof. For a white surface to work most efficiently it needs to be kept clean. If it ends up covered in dirt, mould etc then that won't reflect the sun's energy as much as the white surface should so as the roof gets dirtier and dirtier, any benefits of having it white will diminish also. The roof could be cleaned down regularly - e.g. once a year is probably the most common cleaning time frame for cleaning exterior surfaces, but they'd need to budget for that if they decided that was the best option.

We have a MoulDefender inhibitor which can be added to the paint in some Resene ColorShops as extra defence against moss and mould. It won't stop it completely as often it will start to grow in dirt and contaminants that get lodged on the roof but can act as a booster shot and inhibit moss and mould growth.

Q. We require a suitable product for coating Perspex roof panels over a patio. The surface has become opaque with age but is clear when wet. We'd like the clear look.

A. The only product we have would be Resene Clearcoat UVS. Ensure the surface is clean and free of mould/algae/detritus then apply a coat of the clear. We cannot guarantee how clear the final outcome will be but it should be an improvement over the current dry appearance.

Q. What paint is recommended for repainting over butynol? I have a roof section that has a thick white paint that is breaking away where lichen grew.

A. If there is fall on the roof any Resene exterior acrylic (two coats) can be used after a clean down using Resene Paint Prep and Housewash. If there is little fall then prime the bare butynol with Resene Membrane Primer before topcoating.

Suggest that you treat the roof twice a year with Resene Deep Clean to reduce lichen growth.

Q. I notice that the label for Resene Summit Metallic roof paint says to seek advice from the Resene ColorShop on how to apply the product.

A. The advice to contact Resene was more when the product was sprayed. If painted the surface needs to be sound. If not then it needs to be prepared and primed with an appropriate priming system (Resene Galvo Prime if the roof is new or Resene Galvo One if weathered beyond six months). Then apply two coats by brush. Brush applications will initially not give a uniform appearance but this will develop upon weathering. Ensure the tinted paint is well stirred prior to use each day.

Q. I have just repainted my roof with Resene. I collect drinking water off the roof. How much rain (in mls) do you need before the downpipes can be reconnected to collect water again?

A. Disconnect roof downpipes until after the first shower of rain in order to flush away surplus non-toxic wetting agents before the surface is used for the collection of drinking water.

We have not attempted to relate the amount of rainfall to the time required for disconnection. The wetting agents are considered nontoxic but depending upon the concentration present in the water tank result in the water being foamy or tainted when consumed.

The newly painted roof would need to be washed to the point of a reasonable runoff, preferably over a sustained time rather than a short showier of rain for the best result.

You can place a large clean bucket or water container at the run off collection point to the tank and check the water for taste or foaming and then make a decision on reconnection.

Q. How should I paint an old concrete tile roof? I have removed all the moss and need to know what prep coats and topcoats are recommended.

A. Treat the cleaned roof with Resene Moss & Mould Killer diluted and applied to label directions. Leave for 48 hours then wash down with copious amounts of freshwater and allow to dry. Then apply a saturation coat of Resene Sureseal and finish with two coats of Resene Summit Roof tinted to your selected colour; if using dark colours then have the Resene Summit Roof tinted to the Resene CoolColour™ formulation.

Q. Does Resene have a product to paint modern rubber butynol roofing?

A. Yes if the butynol has a fall then apply two coats of Resene Lumbersider (low sheen) or Resene Sonyx 101 (semi-gloss) in a Resene CoolColour™ formulation. If there is no fall then apply a coat of Resene Membrane Roofing Primer before topcoating as above. If the butynol has started to chalk then scrub down with Resene Paint Prep and Housewash then apply the Resene Membrane Roofing Primer and then topcoat as for new.

Q. I am treating rust on Decramastic tiles prior to painting. Do I use Resene Rust Arrest followed by Resene Galvo One?

A. Application of any solventborne paint to a surface that has a bitumen layer will cause bitumen bleed into the paint. For this reason we normally recommend priming bare galvanising or bitumen on Decromastic type roofing with Resene Galvo-Prime which is waterborne. However Rust Arrest remains our best primer for treating red rust - ensure the rusted areas are well washed to remove salt and wire brush to remove loose corrosion products then apply the Resene Rust Arrest to the prepared red rusted areas. Allow to cure overnight then overcoat with Resene Galvo-Prime. Then apply two coats of Resene Summit Roof.

Q. What primer do I use on a galvanised iron roof to go under Resene Crown Grey Friars? The roof is two years old. And also what primer do we use on Villaboard? What is the coarse grit splatter paint to go on top called, to give a rough cast look?

A. Resene Galvo One for the galvanising, Resene Concrete Primer for the Villaboard then Resene Resitex Coarse (assume not interior).

Q. What paint do I need to paint a concrete tile roof and also paint bare cedar weatherboards?

A.The roof needs to be clean of moss/mould/algae and accumulations of dirt. Treat first with Resene Moss & Mould Killer diluted to label directions then high pressure water wash. Remove large lumps of moss etc before treating with the Resene Moss & Mould Killer solution. When dry apply a saturation coat of Resene Sureseal and finish with two coats of Resene Summit Roof. The success of painting is determined by the initial cleaning steps.

For the weatherboards: if new then apply a coat of Resene Wood Primer and then two coats of a Resene exterior acrylic paint. If weathered treat any areas of moss/mould/algae with Resene Moss & Mould Killer following label directions then apply a coat of Resene TimberLock and then the system for new Cedar.

Q. We are looking at painting an old roof which is either zinc or galv. It has patches of surface rust which have not gone right through. Can you please recommend a system that we can use that will stabilise/convert the rust and then to topcoat?

A. There are products that claim to convert rust to an inactive layer but in my experience they seldom function where there is advanced rusting. Our recommendation would be to wash down using Resene Roof and Metal Wash, and then prepare red rusted areas using a power wire brush or a M3 Rust and Paint Removal Disc. Paint up to the red rusted areas with Resene Galvo One, allow to cure for 16 hours then apply Resene Rust-Arrest to the red rusted areas overlapping onto the Resene Galvo One primer. Then apply two coats of Resene Summit Roof.

Q. Is there a special paint I can put on the tin roof of my sleepout to deflect the heat? The roof is low so temperatures are very high in summer.

A. Resene CoolColours increase the heat reflected for a given colour but the amount does vary with the colour. For maximum heat reflection use white.

Q. What paint would be best over a Suntuff Polycarbonate roofing system? We would like to block out some excess light on a school veranda.

A. You can use any Resene exterior acrylic topcoat (two coats) applied to the clean substrate. However this will give total UV block. We have no semi-transparent product for this application.

Q. I have just repainted my roof with Resene. I collect drinking water off the roof. How much rain (in mls) do you need before the downpipes can be reconnected to collect water again?

A. The statement we make is as follows:
Disconnect roof downpipes until after the first shower of rain in order to flush away surplus non-toxic wetting agents before the surface is used for the collection of drinking water.

We have not attempted to relate the amount of rainfall to the time required for disconnection. The wetting agents are considered nontoxic but depending upon the concentration present in the water tank result in the water being foamy or tainted when consumed.

The newly painted roof would need to be washed to the point of a reasonable runoff, preferably over a sustained time rather than a short showier of rain for the best result. You can place a large clean bucket or water container at the run off collection point to the tank and check the water for taste or foaming and then make a decision on re connection.

Q. What would we use to paint a COLORSTEEL® roof at the beach? Steel is still in good condition but has been renailed and a plumber advised we should repaint it.

A. Wash down with Resene Roof and Metal Wash following label directions then you can use either Resene Hi-Glo (gloss) or Resene Summit Roof (satin).

Q. My COLORSTEEL® roof has in the past been painted a light moss green colour. This is now the existing colour. I would like to paint it Resene CoolColour Element. A staff member told me the roof needs to be painted white before it is painted with CC Element. My painter however has said that as the roof is already a somewhat light colour that painting the roof white first is unnecessary. Please can you confirm which is correct?

A. ReseneC RoolColours will reflect more heat than the same colour applied using non CoolColour technology. The colour Resene Element is nearly black. A white or Resene Galvo-Prime (has CoolColour properties) will give the maximum heat reflection to the CoolColour painted surface. When we test cool colours we always apply the two coats of topcoat over a white basecoat. You definitely need two coats of CoolColour topcoat and the white or Resene Galvo-Prime undercoat is an option, but for black colours a white basecoat is recommended.

Q. Painting a pre-painted roof with Resene Summit CoolColour in Resene Ironsand. Do I need to undercoat as part of the CoolColour system?

A. If you are looking to get the maximum Resene CoolColour™ benefit then apply a basecoat of Resene Galvo-Prime and then apply the two coats of Resene Summit CoolColour.

Q. I recently browsed looking for some type of sealer (undercoat) for a concrete tile roof. It must be sprayable with good bonding with a topcoat. The existing concrete tile topcoat has weathered away.

A. We specify Resene Sureseal as the primer/sealer for bare, old and weathered cementitious surfaces followed by two coats of Resene Hi-Glo or Resene Summit Roof.

Q. I want to paint my old COLORBOND® roof with Resene Summit Roof Metallic Aluminium. Which primer, if any, should I use? And what is the best method of application for this metallic paint - spray or roller?

A. Scrub down with Resene Roof and Metal Wash following the label directions. Prepare flaking or corroded areas using a 3M Rust and Paint Removal Disc (feather back flaked areas to to a sound edge ) and immediately spot prime with Resene Galvo One. Then apply two coats of Resene Summit Roof, best by airless spray.

Q. Someone has suggested that I use a soft broom to paint my roof. Do you have any advice as to whether this will work or not? I'm only really worried about the longevity of the paint finish.

A. An old practice, but the concern is that brooming may apply an uneven coat of paint and this will impact upon performance.

Q. I'm looking to recoat my iron roof. I note some professional firms use elastomeric paint. Do you have anything like this?

A. Elastomeric paints are best applied to cementitious substrates with a history of cracking. We are aware of the use of this type of generic coating for roofing but do not position our product Resene Flexicover E for metal substrates. We recommend using Resene Summit Roof paint.

Q. What does the LVR% become for the roof colour Resene Grey Friars, currently 8, with Resene CoolColour technology? We would like a darkish grey roof as we have black aluminium joinery on white weatherboard, but don't want to generate excessive heat, contraction and expansion.

A. LRV (light reflectance value) is a measure of light reflection and is not related to heat reflection. Hence the LRV of the non-cool and cool versions of a given colour are the same.

What does change is TSR (total solar reflectance). TSR is a measure of the reflection of near infra-red radiation. IR is what keeps us warm. While a cool colour does not render a surface cool to touch the Resene CoolColour™ version will reflect more heat compared to the non-cool version of the same colour.

Q. Our roof painter wants to use Resene Summit Roof on the roof, barge boards and fascia. Will that paint be ok on the timber fascia?

A. Resene Summit Roof can be used over a suitable primer on most substrates. The product has been formulated primarily for roofs. Generally for timber, Resene Lumbersider is more commonly used.

Q. I painted our roof a year ago and have noticed over the past few months that the paint is now blistering particularly where the purlins are. This blistering is in sections across the roof and in some places there is evidence of white corrosion. I have recently purchased Resene Galvo One to prime these areas, however removing the blistered paint is proving to be difficult. The electric drill with wire brush attachment is very slow, hand wire brush doesn't work at all.

A. I have used a 3M Rust and Paint Removal Disc (drill attached) for the purpose of preparing corroded areas of roofing. The disc is more efficient at removing loose paint and underlying corrosion deposits than a power wire brush.

Q. Does Resene Moss & Mould Killer affect Butynol roofing?

A. At the usual dilution rates for the product there are no known effects upon Butynol. There will be a white residue left if the product dries on the surface but this should rinse off with water.

Q. I have a shed which has a plywood roof and walls. I want to waterproof the plywood roof. Have you suggestions on which paint I could use?

A. Prime with two coats of Resene Quick Dry waterborne primer undercoat then apply coats of Resene Sonyx 101 in your selected colour. This system will give weather proofing but not waterproofing.

Q. We want to paint our concrete roof tiles. Do you have a paint for this job?

A. Assuming the tiles are clean and sound the recommended system would be to saturate the tiles with Resene Sureseal then apply two coats of Resene Summit Roof. The success is wholly dependent upon the initial cleaning of the roof. From experience we woud also recommend that the cleaning includes a treatment for moss, mould and algae as well as lichen.

Q. I am about to paint our corrugated iron roof. It is in reasonable condition and was last painted about 12 years ago in green. Part has faded and part is newer in green COLORSTEEL®. I want to paint it all in mid grey. Is it ok to spot prime or do I need to apply a full coat of Resene Galvo-One primer? If I don’t need to apply a full coating of primer can I use Resene Hi-Glo CoolColour™ on top of the existing surface?

A. Scrub down using Resene Paint Prep and Housewash, prepare flaked areas back to a sound edge using a 3M Rust and Paint Removal Disc then spot prime these areas with Resene Galvo-One primer and follow this with two coats of Resene Summit Roof CoolColour™ version of the colour.

Q. I need to repaint a roof which has shingle tiles (the kind with granules on them). Some of the granules have worn off in some areas. What are the best products for cleaning then repainting such a roof? I will be spraying the roof and preferably waterblasting to remove lichen etc. Will waterblasing cause problems for the existing surface?

A. Apply Resene Moss & Mould Killer to the roof taking particular care to saturate lichen growth. Leave the roof to weather for at least two weeks then waterblast to remove lichen growth. Waterblasting may remove a quantity of the original chip so we suggest that you disconnect your downpipes during waterblasting and for the duration of time after the Resene Moss & Mould Killer treatment. Prime any bare areas of base metal or bitumen with Resene Galvo One then apply two coats of Resene Summit Roof.

Q. I need to repaint a COLORBOND® roof and I want to know if your paint system will reduce the heat inside the house.

A. If the roof has weathered for at least a month you can apply Resene Summit Roof to the washed roof (use Resene Roof and Metal Wash to clean it down first). If you use the CoolColour™ version of the colour you select this will reflect more heat than the same colour produced with conventional colour pigments. The effect this may have an effect on the interior temperature wich will vary from project to project.

Q. The paint on my roof has oxidised, white powder on fingers etc and I wish to repaint. I can waterblast but would prefer a less aggressive wash if possible. Do you have a product for this cleansing?

A. Application of Resene Paint Prep and Housewash, while wet scrub down and then wash off using fresh water is our recommendation for removal of surface chalking. Care needs to be exercised as the surface can become slippery. Also if you are using the roof for collection of drinking water you will need to disconnect downpipes to the collection tanks during preparation and for a few showers of rain after painting.

Q. I am planning to paint Resene Summit over asphalt tile roofs – what preparation will I need to do?

A. Prepare with Resene Deep Clean, then leave for at least 2 weeks then waterblast. Apply 1 coat of Resene Membrane Roofing Primer over the bare asphalt the 2 coats of Resene Summit Roof.

For simply restoring colour, Resene Summit Roof works well. A thorough clean-down and removal of moss and lichen is required before coating (old chip tiles are often covered in organic matter, especially south-facing surfaces). Whether a primer is required really depends on the amount of chip remaining on the roof and the condition of the roof. Resene Summit won’t be suitable for re-chipping. For most people the work would require a professional painter.

Q. Many years ago I bought a Resene roof paint which gave a rather rusty roof many years more life. It had metallic flecks in it. What is the new equivalent?

A. If it was a waterborne paint then it probably was Resene Hi-Glo Metallic which has now been replaced with Resene Summit Roof Metallic. The product contains a pigment known as micaceous iron oxide (MIOX) which lays down like overlapping fish scales in the paint film; the pigment reduces the moisture vapour transmission of the coating and thus improves corrosion resistance. However application of an appropriate priming system to bare galvanising/Zincalume is the key determinate of corrosion resistance. The topcoat is usually considered to be more decorative than functional.

Q. We had a first topcoat of Resene roof paint applied around 2pm Friday. The section of roof that is south facing did not dry before it got cold and started to rain overnight. This morning the paint is still wet (can wipe it off with my fingers) and has completely washed off in places. The question is, will it eventually dry out and retain any durability, or are we better to waterblast it completely off and start again?

A. This is an application issue. If the painted area is waterblasted to remove loss or uncured paint then there is no re-application issue as long as the paint is applied under conditions that meet the film forming requirements of the paint.

Q. I need to overpaint a COLORBOND® roof. The surface has gone chalky, but no rust. What is the best procedure and product?

A. Scrub down using Resene Roof and Metal Wash, rinse clean with fresh water and allow to dry. Then apply two coats of Resene Summit Roof in your selected colour.

Q. I am due to paint a corrugated iron roof with a dark blue colour. As it is a 15 year COLORSTEEL® steel roof will it be ok just to spray it with your normal acrylic roof paint or will I have to apply an etch primer or similar first? The roof is in very good condition and we shall be waterblasting it. The reason I am asking is because I am concerned about the adhesion of the new paint to the COLORSTEEL® paint system. Some years ago when I painted a COLORSTEEL® roof the paint system did not adhere correctly.

A. If you have a standard COLORSTEEL® coated roof then as long as the roof coating is clean, sound, and weathered you can apply either Resene Hi-Glo or Resene Summit Roof without the need for an adhesion primer. Both products have adhesion promoters as part of the formulation.

Q. Is there a product that I can 'paint' my roof with as an interim measure following earthquake compounded ageing deterioration - simply to 'delay' eventual replacement? It’s a 20+ year butynol tile-type roof.

A. You can paint butynol but this is only to protect the material from weathering. If there are tears or breaks in the butynol layer we cannot offer a paint system that will give waterproofing. In the event the latter does not apply the following can be undertaken, wash down with Resene Paint Prep and Housewash and prime with Resene Membrane Roofing Primer then apply two coats of Resene Summit Roof. It’s best to avoid dark colours but if you choose a dark colour then use the Resene CoolColour™ formulation of the colour which will give more heat reflection from the painted surface than the same colour made using conventional colorants.

Q. I would like to spray paint my roof and bought your Resene Summit Roof Blue Zodiac for the job. Using an airless spray gun, what size nozzle do you recommend for the best results and what level of thinning with water do you recommend to facilitate easier spraying?

A. For spraying Resene Summit Roof metallic colours we recommend an airless spray unit capable of delivering more than two litres per minute, an LTX 517 tip with a 30 mesh manifold filter, no gun filter. When using a spray unit such as a Graco 395 there is usually no need to thin. When spraying roofs the golden rule is that you can only apply a waterborne paint if you can stand on the roof in bare feet for more than 15 minutes.

Q. I have a trough roof to spray which has started flaking. What is your recommended system to spray finish this? There may be a couple of rust spots.

A. Resene Alumastic unless there is good fall on the roof.