What matters for a painted roof here
A dry window in late winter
Gosford's August (60.4 mm) and September (63.0 mm) are its driest months, which the climate records credit to the foehn effect. February, by comparison, averages 189.9 mm. A primer and topcoats need a run of dry days, and late winter gives you the best odds of getting them.
Summer heat and colour
Gosford hit 44.8 °C in January 2013. Colour decides how much of that heat the roof soaks up. NSW BASIX calls a roof light below a solar absorptance of 0.475, medium from 0.475 to 0.7 and dark above 0.7, and BlueScope says light roofs can run up to 35 degrees cooler on the surface than dark ones in hot sun.
Sun and salt on the coating
Dulux says some fading is normal as roof coatings weather, partly from chalking (UV breaking down the acrylic binder), and that regular washing helps. If you're overpainting steel in salt-spray areas, BlueScope suggests a system with better corrosion resistance, such as a zinc-rich primer.
Older roofs and asbestos
If the house was built before 1990, part of the roof could be asbestos cement. It must never be pressure cleaned before painting, which is illegal in every state. ASSEA's advice is to keep asbestos cement sealed and in good condition rather than cleaning it.
What paint can and can't do
Monier says respraying a roof is cosmetic and won't repair it. On concrete tiles the colour coat plays no part in waterproofing and needs redoing about every five years to keep the look. Terracotta doesn't need painting, and Monier doesn't recommend it.
On COLORBOND steel, overpainting voids BlueScope's warranty. If the steel is sound and you're simply after a new colour, weigh that up first. And if the roof feeds a drinking water tank, confirm the paint system is suitable before anyone starts.
In NSW, protective coatings on a metal roof count as roof plumbing work, so a job over $5,000 needs a roof plumbing contractor licence.
Before you choose who paints it
- Which coating system, by brand and product, and how many coats?
- What's your plan if rain arrives halfway through?
- What's the solar absorptance of the colour I've picked, and is that light, medium or dark under BASIX?
- How will you clean the roof first, and have you checked whether any of it is asbestos cement?
- If it's Colorbond, have you explained that painting voids the BlueScope warranty?
- What do I have to do to keep the coating warranty valid?
How we'd approach it
We'd only paint a roof that's already watertight, and we'd book it for August or September. On concrete tiles, a lighter colour is worth considering if summer heat bothers you. On sound Colorbond we'd think twice about painting at all, because the factory finish and its warranty are hard to beat with a brush.
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.