The streaks are caused by a type of algae known as gloeocapsa magma.
What causes black streaks on roof shingles.
Why are there dark streaks on my roof.
Over time this algae accumulates developing a black outer coating which causes stains on roof shingles.
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.
This algae growth usually begins as small spots and then eventually becomes visible streaks.
While the streaks do not cause a great deal of damage they can cause the shingle to age prematurely.
If you re seeing black streaks running along your roof chances are you ve mistaken them for dirt or even mold.
They re actually algae otherwise known as gloeoapsa magma and they are as nasty as they are resilient.
As the blue green algae.
The most common type is known as gloeocapsa magma also known as blue green algae.
Algae growth may cause discoloration on roofs resulting in brown or black streaks on a rooftop.
The black streaks running down roofs are actually a hardy algae called gloeocapsa magma.
Black streaking on roofs is a common problem.
Most black streaks form on the northern slopes of roofs where it s darker and wetter ideal for algae growth.
Algae growth on asphalt shingles.
Black streaks on shingled roofs are a common though mysterious sight.
Here s what they are and what to do about them.
Algae arrive on the rooftop through the air in the form of spores or clumps of cells.