Commonly found in climates with warm humid summers it does no damage to the roofing but it certainly does looks bad.
Algae growing on roof shingles.
It can be brown gray blue or green.
Black streaks green or white spots round lichens mosses green moss that spreads across your roof.
The best way to get rid of algae once it s taken hold on your roof is to have a professional roof cleaning team come with a low pressure washer and cleaner that will kill the algae and mold but not hurt the plants and grasses around your home.
A blue green algae known as gloeocapsa magma could be the reason you have the algae which is spread by airborne spores.
Algae growth is common on roof surfaces of several materials including asphalt shingles concrete and clay roof tiles and even slate.
It appears on the shingles in streaks that head down the roof pitch vertically.
Often algae that is identified as green when studied microscopically also looks black or quite dark on a roof surface.
Although mold can grow in your roofing materials if water gets trapped somewhere if you see any of the following on top of your roof algae are more likely your problem.
If you have noticed black spots or streaks on your roof you ve got algae on your roof.
Algae will grow flush against the shingles and fixtures on your roof.
Algae growth won t cause any structural problems to your roof but it looks ugly and it can damage the shingles over time.