A stained roof is infected by a Cyanobacteria called Gloeocaspa Magma that thrives in moisture and feeds on roofing material. To learn more about this ancient nemesis (often called "Roof Algae") please visit this link: http://en.wikipedia.org/wiki/Gloeocapsa_magma.
WHY are millions of roofs nationwide becoming infected?
The bacteria is wind-borne and spreads from infected roofs to a clean neighboring roof. It is not caused by trees or pollutants; however these do increase the growth rate after infection. The bacteria requires moisture and prefers a humid climate, yet it can survive even in an arid climate (provided there is some morning dew). For this reason, you will notice the first signs of infection on the North side of your roof, yet as it matures it will spread to all areas of your roof. Due to our climate, every single roof in Southeast Texas will become infected at some point (usually within 6 years of getting a new roof). This epidemic is relatively new (about 30 years in the making) due to roofing manufacturers adding limestone to the shingle composition in order to make the shingles heavier and more wind-resistant. The limestone (calcium carbonate) provides the primary food source for the "roof algae".
HOW can homeowners prevent infection?
The roofing manufacturers addressed this roof stain issue years ago, and issued a national bulletin detailing how to remove the stains and prevent damage. To view the ARMA Bulletin and its prescribed cleaning method please visit this link: http://www.asphaltroofing.org/algae-discoloration-roofs
Sparkling Roof cleans all composite shingles exactly to the ARMA specifications with the exception of using a Bio-friendly surfactant instead of the trisodium phosphate. Our cleaning method is a soft-wash chemical rinse (less PSI than light rainfall) and will not damage your roof or property. To learn more about our cleaning method please click HERE.