What Causes Black Streaks 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.

What causes black streaks on roof shingles.

Most black streaks form on the northern slopes of roofs where it s darker and wetter ideal for algae growth. Why are there dark streaks on my roof. Algae growth on asphalt shingles. Black streaks on shingled roofs are a common though mysterious sight.

Algae may be mistaken for soot dirt or tree droppings most of which typically produce only localized discoloration. Algae growth may cause discoloration on roofs resulting in brown or black streaks on a rooftop. As the blue green algae. This algae growth usually begins as small spots and then eventually becomes visible streaks.

Black streaking on roofs is a common problem. The streaks are caused by a type of algae known as gloeocapsa magma. The most common type is known as gloeocapsa magma also known as blue green algae. If you re seeing black streaks running along your roof chances are you ve mistaken them for dirt or even mold.

The black streaks running down roofs are actually a hardy algae called gloeocapsa magma. While not immediately damaging they can prematurely age 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. Here s what they are and what to do about them.

Over time this algae accumulates developing a black outer coating which causes stains on roof shingles.