A common question we get from our inspection clients is “what is that black streaking on the roof?” No, its not water, dirt or mold. It’s actually algae, often called “black algae” by our inspectors. The algae usually starts as small spots, and becomes more visible to a homeowner after a couple months of growth.
The algae is not harmful or dangerous in itself, but can cause the protective UV granules that cover roof shingles to come off, exposing them to the elements.
Fortunately, there is an easy solution to your black algae problem, which is to schedule a professional roof cleaning. DIY roof cleaning methods are not advised due to the dangerous nature of climbing on your roof, and may actually void any roof warranties you may have.
While there is no way to permanently rid of black algae, regular roof maintenance will reduce the frequency in which it becomes a problem at your home, which includes trimming trees and shrubs away from your roof.