While Distinctive Metal Roofing installs stone coated metal roofing materials occasionally, we caution those living in heavily shaded/wooded locations against it due to potential mold and algae growth. With their heavily granulated surface that retains mold and algae, if you’re currently having problems with mold and algae growth on your roof, stone coated shingles are not the choice for you. Please keep in mind that asphalt shingle streaks are also caused by the large percentage of limestone as a filler material. Limestone is what black algae feeds on which means black algae streaks appear early in the life of an asphalt shingle. Stone coated metal roofing does NOT contain limestone (the granules on stone coated metal panels is crushed ceramic or granite) but the granular surface itself can be an issue.