Why roofs here go green and black
Humid, with no dry season
The coast's climate is humid subtropical with no dry season, and afternoon humidity at the airport sits around 66% across the year, peaking at 71% in February. Roofs that rarely dry out properly are where mould and lichen thrive.
A fibro past
The earliest beach shacks on the north coast, built between 1914 and 1946, often used fibro cement and other recycled materials, and much of the coast was built in the decades before asbestos was phased out by 1990. Have an older roof tested before anyone cleans it.
Tiles, metal and plastic sheeting
Monier says terracotta grows more moss and lichen than concrete, though only on the surface. Polycarbonate skylights and patio sheets need care too: Laserlite says a water blaster strips part of the UV cap and shortens the sheet's life.
Cleaning methods that won't do harm
For tiles, Monier strongly advises against pressure washers because of the risk of damage, and suggests a professional cleaner. For COLORBOND steel, BlueScope's approach is mild household detergent, water and a soft broom, then a fresh-water rinse. BlueScope also says not to use sugar soap and some other cleaners on bare ZINCALUME.
Asbestos cement is a different story. It's illegal in every state to pressure clean it, and ASSEA says pressure cleaning asbestos roofs has spread fibres to neighbours' properties, footpaths and stormwater, with clean-ups costing hundreds of thousands of dollars. Queensland suggests a fungicide and sealant instead. Our national roof cleaning page covers the options.
Keep off the roof
Mossy, lichen-covered roofs are slippery, and fibro or old sheeting can break underfoot. ASSEA notes people have fallen through or off asbestos roofs while doing maintenance. Leave all roof work to someone with fall protection, and never walk on a roof that might be asbestos cement.
Questions for a Sunshine Coast roof cleaner
- Has my roof been checked for asbestos, and what happens if it is?
- What method and pressure do you use on tiles?
- What chemical treatment do you use, and is it safe for my tank and garden?
- How will you protect the gutters, downpipes and skylights?
- Will you photograph any damage you find?
If we were booking
We'd confirm what the roof is made of first. On anything that might be fibro, we'd skip cleaning and talk to a licensed asbestos contractor about sealing. On tiles or steel, we'd choose a low-pressure clean in late winter, when the roof has the best chance of drying out. The Sunshine Coast hub has more on local conditions.
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.