Green Algae Roof Shingles

Black or brown or green algae stains on asphalt roof shingles.

Green algae roof shingles.

Commonly found in climates with warm humid summers it does no damage to the roofing but it certainly does looks bad. If you live in a humid area of the country you ve probably seen unsightly dark streaks on asphalt shingle roofs. The black mold like stains and streaks that appear on roofs particularly light colored asphalt shingles is actually a blue green algae gloeocapsa magma. Here in oregon mostly blue green algae grows on the outside of the house or on the roof shingles.

The only way to take care of it is to use a high base chemical solution like zinc sulfate. The most common culprit is actually a blue green algae known as gloeocapsa magma that is spread by airborne spores. Many homeowners mistake algae for roof mold in most cases however it is really a blue green type of algae and when it dies it leaves dark streaks on your roof. Misnamed as mildew or fungus by some writers algae staining on asphalt shingles usually in shaded areas or on the more shaded roof slopes characterized by black staining fairly uniform over shingles but appearing specifically in areas of the roof shaded by nearby trees.

We ll explain more of that in a bit. Though often attributed to an accumulation of dirt defective shingles mold or mildew. Algae can cause unsightly stains and growths on your new roof. What is roof algae.

A roof may develop different types of algae lichens and fungi as bacteria take over.