In the Northeast, there is a chronic issue of mold, mildew, and algae collecting on rooftops. The cause is due to a combination of factors including the wet and humid environment that offers ideal living conditions for the growth of algae, mold, and mildew. Another factor that causes these stains is that these microbes feed on limestone and the fillers contained in the asphalt shingles that cause the degradation of your roof over an extended period.
A professionally cleaned roof is a benefit to the lifespan of your roof. The most apparent benefit is the look of a clean roof which is more pleasing aesthetically. Another lesser known fact is that a clean roof increases the energy efficiency of your home. A clean roof reflects and displaces the heat of the sun as it was designed to function.