Keeping Your Roof Clean Will Help Save You Money

Algae: The black stains are called gloeocapsa magma or GM. GM algae is a bacterium that feeds off of both asphalt and limestone roofing in moist, cool and shaded areas of the roof. When there is minimal light, GM forms a blue-green color. The more shaded areas of the roof are more likely to have these algae, which can harbor various types of molds. This explains why some roofs are stained only on one side.

Lichens: The combination of algae and fungus creates lichens and described as a fungus that grow symbiotically with algae. These plant-like organisms form a branching growth of “root-like tentacles that penetrate deep into the shingle’s organic, oil base for nourishment.” Lichens are tough to remove from the roof and can reappear from humidity and rain. 

Moss: Unlike the algae and lichens, moss is an actual plant. Moss has a shallow root system and requires a lot of moisture to survive. Areas with less sunlight remain damp longer. Overhanging tree branches not only provide more shade, but they also drop debris that serves as a food source for moss. Like algae, moss spores are often transferred by wind or animals and can easily spread throughout neighborhoods. 

SHINGLE DAMAGE: As mentioned above, algae is a bacterium that feeds off of both asphalt and limestone. That means that these organisms are literally eating away at your shingles. Furthermore, roofs with algae stains absorb heat. This results in an extremely high heat in the attic, which can reduce the lifespan of the shingles by essentially baking them from the inside out.

Lichen colonies can be quite damaging to shingles. The penetrating tentacles create pock marks where they grow and eventually ruin the shingles.

Moss is even more detrimental to roof shingles. Moss can cause the edges of the shingles to lift or curl—often the first sign that a roof replacement is needed. And because moss holds in moisture, it can freeze in the winter, causing even more shingle damage.

WOOD ROT: Moss has the ability to hold in moisture and divert water, which makes your roof deck susceptible to wood rot and leaks. Moss tends to grow in the slots between shingles, which is the last place water evaporates from a roof.

Moss growth on your roof is easy to spot. But the signs of wood rot are not always obvious to the average homeowner. You may have a leak and you don’t even know it. This will cause even more wood damage.

Wood rot not only shortens the life of your roof, it can cause mold growth, which can be hazardous to homeowners and their pets.  Unwanted animals, such as squirrels, have been known to cause roof and attic damage by chewing through areas of the roof and supporting wood systems. Rotted wood makes it easier for these creatures to bore through.