Blue Green Algae On Roof Shingles

Algae can cause unsightly stains and growths on your new roof.

Blue green algae on roof shingles.

Algae can grow in moist shaded areas so if a homeowner has trees hanging over their roof tell them to trim them back to let the sunshine warm and dry the roof. The black stains you see on your roof aren t the algae itself but a hard dark coating it creates to protect itself from the sun s harmful ultraviolet rays. If you ve noticed it on your roof you may have mistaken this common algae for mold or mildew. Algae is airborne meaning if your neighbor has it it s likely that you ll get it too.

It usually grows in the north and west areas of the home. Commonly found in climates with warm humid summers it does no damage to the roofing but it certainly does looks bad. The black mold like stains and streaks that appear on roofs particularly light colored asphalt shingles is actually a blue green algae gloeocapsa magma. Blue green algae usually brings images of lakes and waterways clogged with algae causing damage to the ecosystem not a roof.

If a new roof is in order then suggest gaf shingles with stainguard protection to help ensure the beauty of a roof against unsightly blue green algae. A roof may develop different types of algae lichens and fungi as bacteria take over. However algae is commonly found on roofs across the usa and canada. Typically it will appear as dark black stains or streaks.

While it doesn t cause substantial damage to the roofing surface the black streaks can certainly make it ugly. According to algae expert michael guiry algae base at references some of these black algae are as identified in the lab blue green or even lichenized algae while others are a diverse group of coccoid algae like our microscope photo of more green algae from a roof sample below that are turning out be be very diverse. Many homeowners mistake algae for roof mold in most cases however it is really a blue green type of algae and when it dies it leaves dark streaks on your roof. A blue green algae known as gloeocapsa magma could be the reason you have the algae which is spread by airborne spores sometimes it can also be caused by an accumulation of mildew mold dirt or defective shingles.