The DARK STAINS you see are a form of algae called Gloeocapsa magma which is a species of cyanobacteria. New England's humid summers actually promote moisture and algae growth on the north side of your Amherst colonial.
Roof algae hold the moisture and will begin to break down your shingles. Because of the bacteria, the shingles will rot prematurely. Lichen is one of the most common signs of damage. Lichen eats away the roof granules that provide protection to shingles.
The north side receives less sunlight, this area stays damper which allows the algae spores to thrive and grow. In addition, some shingles have limestone added to them as filler which is a great food source for algae.
Blue Sky Power Washing can clean your roof! Call us today 603-594-WASH (9274) and visit www.blueskypowerwashing.com, to see how we do it!
