What Causes Mildew On Roof Shingles

Black algae stains may be mistaken for but are not extractive bleeding a product cosmetic defect.

What causes mildew on roof shingles.

What causes black mildew on shingles on north side of roof and how can get rid. If you live in a humid area of the country you ve probably seen unsightly dark streaks on asphalt shingle roofs. Though often attributed to an accumulation of dirt defective shingles mold or mildew. I suffer from two of.

Answered by a verified home improvement expert we use cookies to give you the best possible experience on our website. Apparently the sodium causes an electrochemical reaction that reduces the elasticity of the asphalt leading to stiffness brittleness and curling of the shingles. Unlike algae moss can be detrimental to asphalt shingle performance. Some black stains on asphalt roof shingles are caused by a black algae typically gloeocapsa magma.

There is some concern regarding the use of chlorine based products on asphalt roofs. Household bleach can damage asphalt due to its high sodium content. Missing shingles a heavy storm can blow shingles off a roof especially on houses where the shingles have been weakened due to the growth of moss mold mildew or algae. The most common culprit is actually a blue green algae known as gloeocapsa magma that is spread by airborne spores.

Black algae stains on asphalt singles some black stains on asphalt roof shingles are caused by a black algae sometimes misnamed as a black fungus or even a mildew such as that shown in the photograph here.