A dirty roof can ruin your curb appeal, but even worse it can damage the integrity of your roof.
The 3 main culprits that slowly deteriorate your roof are: algae, fungus/lichen and moss. These live organisms literally eat away at your shingles.
The discoloration and black stains you see are actually a photosynthetic cyanobacteria consisting of algae spores called gloeocapsa magma. This bacterium feeds off the limestone in your shingles and once it appears it will spread quickly eventually covering your entire roof. It will stop your shingles from reflecting the sun’s UV rays. When this happens, it will not only affect your home’s cooling and heating ability leading to more costly energy bills, but it will cause the shingles to deteriorate more quickly.