The black streaks running down roofs are actually a hardy algae called gloeocapsa magma.
What causes black streaks on roof shingles.
But now this black algae is termed a roof shingle algae because of the annoying discoloration on a asphalt shingle roof.
Algae growth on asphalt shingles.
The algae feed off of the limestone within the roof shingles.
Algae arrive on the rooftop through the air in the form of spores or clumps of cells.
Most black streaks form on the northern slopes of roofs where it s darker and wetter ideal for algae growth.
Though often attributed to an accumulation of dirt defective shingles mold or mildew.
They re actually algae otherwise known as gloeoapsa magma and they are as nasty as they are resilient.
While the streaks do not cause a great deal of damage they can cause the shingle to age prematurely.
Algae growth may cause discoloration on roofs resulting in brown or black streaks on a rooftop.
Here s what they are and what to do about them.
What are those ugly black streaks on my roof.
Technically the black streaks on roofs are a form of algae known as gloeocapsa magma.
The most common type is known as gloeocapsa magma also known as blue green algae.
Areas of the country with low humidity have fewer instances of roof streaks while the problem is relatively common in the southeast where it s more humid and warm.
If you re seeing black streaks running along your roof chances are you ve mistaken them for dirt or even mold.
Algae may be mistaken for soot dirt or tree droppings most of which typically produce only localized discoloration.
Black stains on an asphalt roof caused by algae.
The black mold like stains and streaks that appear on roofs particularly light colored asphalt shingles is actually a blue green algae gloeocapsa magma.
While not immediately damaging they can prematurely age shingles.
The black streaks are also known as black algae or roof mold.
Believe it or not those black streaks only appear on roofs in certain areas of the country.
Those that tend to be the most humid furthermore they will only appear on the north side of the roof.
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.
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.
If you live in a humid area of the country you ve probably seen unsightly dark streaks on asphalt shingle roofs.
Over time this algae accumulates developing a black outer coating which causes stains on roof shingles.
Although these dark spots and ugly black streaks on your roof may look like dirt mildew soot or mold what they really are is algae.
Why are there dark streaks on my roof.
