The black mold like stains and streaks that appear on roofs particularly light colored asphalt shingles is actually a blue green algae gloeocapsa magma.
How to clean black streaks off roof.
Most formulas contain chlorine bleach and or trisodium phosphate tsp and water.
But now this black algae is termed a roof shingle algae because of the annoying discoloration on a asphalt shingle roof.
Over time this algae accumulates developing a black outer coating which causes stains on roof shingles.
The streaks are caused by a type of algae known as gloeocapsa magma.
The algae feed off of the limestone within the roof shingles.
An internet search on how to clean black streaks on your roof will turn up several different homemade formulas as well as commercial brands for getting rid of roof algae.
Now if you live where cleaning off mildew from exterior surfaces is a constant chore the just hit the moss with the same bleach solution.
The black roof stains are caused by a form of algae that has been around for years typically found in the woods on the north side of trees or on exposed rocks.
While doing little harm to your shingles the black streaks caused by the algae are unsightly.
Unlike black algae stains which come off immediately with the rinse phase of the cleaning dead lichen and moss will require a few heavy rains to finish rinsing off the roof.
Tim asks how can i clean the black stains off my roof and keep them from coming back your stains are probably caused by the airborne spores of a blue green algae.
While the streaks do not cause a great deal of damage they can cause the shingle to age prematurely.
That ll kill it off but won t inhibit regrowth so just rewet the roof with the bleach solution whenever cleaning off the rest of the place.
Video on how to clean softwash an asphalt shingle roof including where to find.
Read on to find out how to remove them.
Commonly found in climates with warm humid summers it does no damage to the roofing but it certainly does looks bad.
As the blue green algae accumulate they develop a dark hardened outer coating which results in the black stains you see.
Black streaks on the north and west facing and shaded areas of your asphalt shingled roof can really wreck the appearance of your home.
The streaks look like mold but they re actually algae colonies that form in your shingles and feed on moisture and the limestone filler agents in the shingles.