What is the algae (or fungus) found on roofs?
A. In certain moist areas, algae can grow on mineral surfaced flat roofing and asphalt shingles. Although the algae has no proven effect on membrane or shingle life, it does stain or discolor the surface. Commonly (and usually incorrectly) called fungus, this algae staining can be unattractive. The algae-containing stains can be dramatically reduced by the use of special copper granules.
