|What Are Those Black Stains on a Shingled Roof?||Those black unsightly stains are algae. Algae appear as dark to black stains each shingle and usually covers a majority of the roof surface area, more predominantly on the lower portion of the roof where moisture content is higher and taper as they reach the ridge caps.|
|How Does a Roof Get Stained with Black Algae?||Algae can spread from one infected roof to another via airborne spores. These spores land randomly on a roof
and take root. A Shingle is the perfect breeding ground for algae due to its porosity and constant moisture content. A protective sheath creates the dark to black color the algae forms in an effort to protect itself from the sun’s UV rays.
|How Does Algae Grow?||Algae require moisture and proper temperatures to grow. Dew is the primary moisture source. Algae are
found excessively in the Southeast of North America, but it can and will grow anywhere. The algae generally grow on the
northern exposures of a roof since this exposure generally receives less sunlight. Algae are very well adapted to
extreme conditions, meaning they can survive both extreme heat and extreme cold weather conditions.
|What Is The Solution?||It is recommended to install Algae Resistant Shingles. These types of shingles have a specially formulated granule that inhibits algae growth, keeping your roof looking new and algae free for years.
If installing a new roof is not an option, it is recommended to clean your roof with a special roof cleaning mixture. For more information click How To Clean Roof Shingles
|What You SHOULD NOT do!||It is recommended by the leading roofing manufacturers to not power wash your asphalt shingle roof. Power washing shingle roofs can dislodge the granules, which can lead to premature shingle failure. The reflective shingles present in a shingled roof can both reflect the sun’s heat in the summer which will reduce cooling costs and can retain the heat in the winter thus reduce heating costs.|
|Where Can I get More Information?||Visit North America’s largest roofing manufacturer GAF for all the information you need.|