Asbestos cement roofs: no pressure cleaning, ever
It's illegal in every state to use high-pressure water on asbestos materials, so an asbestos cement roof must never be pressure cleaned before painting. Queensland's asbestos authority says to apply a fungicide and sealant instead, and homeowners there can be fined up to $10,000 for water blasting asbestos. If your roof is grey cement sheet on an older home, read painting an asbestos roof first.
What each roof needs
| Concrete tiles | Terracotta | Colorbond or Zincalume | |
|---|---|---|---|
| Worth painting? | Optional, purely for looks | Monier doesn't recommend it; the colour is fired in | Possible, but it voids BlueScope's warranty |
| If you go ahead | Expect to repaint about every five years to keep the look (Monier) | Unglazed only, and it then needs recoating for good | BlueScope says water-based acrylic is generally the most suitable |
| Cleaning first | A professional clean; Monier advises against pressure washers on tiles | The same, gently | Household detergent and a soft broom; scourer pads, never steel wool, on steel under about a year old |
| Watch for | Paint adds no waterproofing | Once painted, always painted | No texture match for Matt finish and no colour match for Metallic |
What roof paint does, and what it doesn't
Paint changes the colour and gives the surface a fresh film. It doesn't fix cracked tiles, failed ridge mortar, rusted-through sheets or leaking flashings.
All coatings fade a little. Dulux says some fading is expected as roof coatings weather, partly from chalking, where UV breaks down the acrylic binder, and regular washing helps. If heat is your reason for painting, start with our page on heat-reflective coatings.
On steel, BlueScope says scratches under 2 mm wide that you can't see from the ground should be left alone, because the metallic coating still protects the steel underneath.
Brands, systems and warranties
We don't rank paint brands. What we'd look for is a named system, with primer and topcoats from one maker, applied by a professional. Dulux's Acratex is one example: Dulux describes its Roof Membrane as a 100% acrylic coating, says the system covers concrete and terracotta tiles, Colorbond, Zincalume and corrugated iron, and offers more than 500 colours.
Dulux offers up to 15 years on film integrity for some Acratex systems, but the period depends on the product, the surface, the number of coats, a professional applicator and ongoing maintenance. A painter's workmanship warranty is separate, so get both in writing.
Acratex is a Dulux product, and Colorbond and Zincalume are BlueScope trade marks. We have no ties to any paint or steel maker.
Rainwater tanks and coastal homes
If your roof feeds a drinking water tank, check the product first. BlueScope says not every roof paint system suits drinking water collection, and the supplier should confirm. Near the sea, BlueScope suggests a system with better corrosion resistance, such as a zinc-rich primer, when overpainting its steel.
Ask before the first coat
- Which product and system are you using, by name, and how many coats?
- Which primer suits my roof, and is it right for salt air?
- How will you clean the roof first?
- Is the system suitable for my rainwater tank?
- Whose warranty applies, for how long, and what would void it?
What you can do
You can
- Choose the colour from a real sample seen in your own light
- Find out whether your roof feeds a drinking water tank
Leave to a roofer
- Cleaning, repairs and all painting on the roof
- Rust treatment and priming on steel
- Anything on an asbestos cement roof
What we'd check first
We'd ask whether the roof needs paint at all. Terracotta rarely does, and painting Colorbond means giving up BlueScope's warranty. If it's a faded concrete roof and the look matters to you, a named acrylic system from a professional applicator is a fair choice, but we'd have the ridges and broken tiles fixed in the same job, because paint alone keeps no water out.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.