Black Roof Stains?
- Insurance will not cover leaks due to Algae
- Lessens the structural integrity of the shingles and causes premature aging
- It makes your home look not maintained, dirty, and is not aesthetically pleasing.
- Manufacturer warranties do not cover algae. If an algae resistant shingle is purchased it probably only covers one type of algae and at most for 5 years. It must be reported within 30 days of its appearance.
IT’S NOT MOLD, IT’S NOT SOOT
The black spots discoloring your asphalt roof are more than likely the pervasive and prevalent algae known as Gloeocapsa magma.
- The first stains usually appear in areas of your roof which receive less light, like areas with heavy tree coverage or north-facing sides of a roof.
- Algae travels through the air, so if one neighbor receives a few spores, the whole neighborhood will soon be sporting the black streaks.
- Unfortunately, they love to feed on the calcium carbonate contained in most asphalt shingles.
- According to Tom Bollnow of the Asphalt Roofing Manufacturers Associations (ARMA), “The algae is mostly an aesthetic nuisance, although with time, the moisture retained in the algae can prematurely age the shingles, void warranties, and cause leaks
Bleeding due to algae caused deteriorating
Bleeding of bituminous (the main ingredient in asphalt) material was readily identified as a surface stain or discoloration on the roofing membrane. Loss of bitumen might signal a reduced roof shingle life for two reasons:
- Shingle bleeding stains may be a clue that the asphalt mix for the particular shingle batch lacked adequate bonding due to the algae.
- The loss of substrate material (the cohesive material) from a shingle may correlate with aging and wear.
A change in shingle weight is the dominant feature appearing in shingle wear. Loss of weight caused by loss of surface materials or loss of membrane materials correlates with shingle wear and life span. Loss of volatile materials is significantly lowers the flexibility of shingles which is another contributing factor to shingle wear and ultimately leads to tears or cracking.
Do you live in an area likely to get algae?
Here in Allentown, Pennsylvania, as you can see by the key on the map below, we have a serious problem, which means we are pretty likely to see these streaks appear across all our shingles roofs across the state.
Does roof algae growth on asphalt shingles affect shingle life?
Two claims of harm caused by roof algae:
- Roof algae causes shingle granule loss? Black algae reduces roof shingle life by “eating” at the shingles which loosens mineral granules and exposes the shingle substrate.
- Roof algae causes shingle tab lifting? Black algae on roof shingles is a cause of shingle tab lifting.
Should you clean your shingles?
Watch Out! Don’t try to clean your asphalt shingles roof without consulting the manufacturer about their recommended cleaning methods. For example, power washers and chemicals may damage the shingles and reduce the life of your roof. Other chemicals such as bleach may cause staining on other areas of your building and can be unsafe if not handled properly.