The dark streaks on the surface of a roof are caused by an algae called Gloeocapsa magma. As this algae builds up from moisture that stays on the roof, it develops a dark, hardened outer coating that can cause your home to absorb more heat. The algae can grow on many roofing materials, including metal, clay tile, slate tile, and asphalt shingles.
How Algae Damages Your Roof and Home
Algae affects both the appearance and the condition of roofing materials. On asphalt shingle roofs, it slowly feeds on the limestone filler, which lowers the durability of the shingles. On clay or concrete tile roofs, algae can grow heavily over time in the crevices and curves of the tiles.
Dark spots also grow on siding, and they are usually a combination of algae, dirt, grime, and mold. Stains can also appear on windows, fences, driveways, and walkways after years of rainfall and debris splashing up from the ground onto the property.
The Best Way to Remove Them
The best way to handle this problem is to have a professional company use the soft washing method on a regular basis. We recommend having all the surfaces of your property properly washed at least once a year to keep its cleanliness and value at their best.
Need help with your home’s exterior? Foundation Pressure & Soft Wash serves McKinney, Plano, Frisco, and Collin County. Call or text (469) 659-7281 or request a free quote.