What grows on, and builds up on, Gold Coast roofs
Damp, warm summers
Afternoon humidity averages 70% in January and February, the wettest part of the year, and about 92 days a year bring at least 1 mm of rain. South-facing and shaded slopes get the least sun and dry slowest, so that's where growth starts.
Moss likes terracotta
Monier says moss and lichen grow more on terracotta, especially unglazed, than on concrete tiles, though only on the surface. It looks worse than it is, but it holds moisture and sheds debris into the gutters.
Salt on sheltered steel
Rain rinses most of a metal roof, but not the sheltered parts under eaves and gutters. BlueScope suggests washing those unwashed areas every three months in coastal areas with salt spray, which for homes near the surf is routine upkeep.
Older homes, older materials
The Gold Coast has been building canal estates and suburbs since the 1950s. If your home was built before 1990, assume the roof could contain asbestos until it's been tested.
How a roof should be cleaned
Monier strongly advises against pressure washers on tiles, because of the risk of damage, and recommends a professional roof cleaner. On COLORBOND steel, BlueScope's method is household detergent and water with a soft broom or mop, rinsed off with fresh water. Solvent cleaners and hard bore water are out.
For asbestos cement there's no safe DIY clean. Queensland's asbestos website says to apply a fungicide and sealant instead of cleaning, and water-blasting carries fines up to $10,000 plus the clean-up bill. Our moss removal page covers treatments, and the national roof cleaning page explains the options.
Stay off the roof
A wet, mossy roof is slippery, and asbestos cement or corroded sheeting can give way underfoot. Safe Work Australia says to treat every roof as fragile until a competent person confirms otherwise. Leave roof cleaning to a professional with fall protection.
Questions to ask a Gold Coast roof cleaner
- How will you clean my roof, and at what pressure?
- Do you check for asbestos before starting on an older home?
- What treatment do you use, and is it safe for my water tank and garden?
- Will you report cracked tiles or rust you find?
- How will you stop debris and run-off blocking the gutters and downpipes?
Our take
We'd book a gentle clean in the drier part of the year, from July to September, when the roof dries quickly afterwards. Anything built before 1990 gets tested before a cleaner sets foot on it. Near the water, we'd rinse sheltered steel every few months and save the full clean for when growth actually shows. The Gold Coast hub has the wider local picture.
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.