Why are my Shingles turning Black?
So do your fiberglass asphalt shingles have black streaks?
The shingles stains are a form of Roof Algae or lichen called Gloeocapsa magma.
Roof Algae Gloeocapsa magma needs three criteria to grow.
Roof mold, lichen, moss and and algae thrive in warm humid environments and normally appear on the North slope where additional shade and moisture support roof algae and roof mold growth. Roof Algae produces its own energy source, and feeds on inorganic materials like calcium carbonate, an asphalt shingle filler material. Feeding on inorganic material distinguishes roof algae from roof fungus and roof mildew, which require organic material to survive.
Thus, elimination of roof algae may reduce roof fungus and roof mildew accumulation; so will removing loose debris from your roof shingle deck and gutters. (Leaves, twigs, and tree bark.)
Roof algae stains are seen in nearly eighty percent of the United States in various degrees.
In Florida your shingles may be completely covered with roof algae in as little as four years.
Also, this particular roof algae strain has become hardier and is able to migrate to less humid environments than it has in the past.
In areas where roof algae is traditionally has been found, roof stains manifest earlier and more severely on a greater number of roofs.
Use of a Roof Stain Cleaner early is essential, otherwise your 25 year roof may only last 12 year, and that is like throwing away thousands of dollars....