Here s why algae grows on roofs.
How did my roof get the black streaks.
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.
Gravity pulls this coating down leaving black streaks on the impacted roof.
If you live in a humid area of the country you ve probably seen unsightly dark streaks on asphalt shingle roofs.
Technically the black streaks on roofs are a form of algae known as gloeocapsa magma.
Thankfully it isn t harmful to your health like mold.
The algae then thrive on the moist crevices of your asphalt tiles.
With each passing year the algae will grow and become more and more noticeable.
The wrong way to remove black streaks from your roof there is a temptation among homeowners to try to address gloeocapsa magna with power washing.
Most likely it started as a small circular patch a slight discoloration from the normal color of your shingles.
Roof algae is most prevalent on north and west facing shingles and in neighborhoods with lots of mature trees.
The streaks are caused by a type of algae known as gloeocapsa magma.
Over time this algae accumulates developing a black outer coating which causes stains on roof shingles.
As the blue green algae accumulate they develop a dark hardened outer coating which results in the black stains you see.
This blackish algae creeps it way across neighborhood roofs gradually turning your home s asphalt shingles an ugly dark brown or black.
The black streaks are also known as black algae or roof mold.
The wind carries the spores of this algae onto your roof.
The algae feed off of the limestone within the roof shingles.
But over time black stains develop as some of the bacteria die off to create a dark tough protective outer coating.
The great news for homeowners is that the most common causesof these black streaks are algae called gloeocapsa magma.
The black streaks that you see on your roof didn t start off as streaks at all.
The algae will worsen and become more noticeable each year trapping moisture and causing premature shingle aging and granule loss.
The most common type is known as gloeocapsa magma also known as blue green algae.
But now this black algae is termed a roof shingle algae because of the annoying discoloration on a asphalt shingle roof.
The algae feed on the limestone in shingles.
The black streaks running down roofs are actually a hardy algae called gloeocapsa magma.
It s easy to miss once it begins but the black patch is an indicator that a predatory bacteria gloeocapsa magma has taken up residence on your.
