How Did My Roof Get Algae

This is what makes those unattractive black streaks on your roof.

How did my roof get algae.

To remove roof algae a solution of oxygen bleach can be applied to the roof shingles and then rinsed off. The most common class of roof algae is gloeocapsa magma a bacterium that eats water and expels oxygen. To keep the algae from coming back insert 6 inch wide strips of zinc or copper under the row of shingling closest to the roof peak leaving an inch or two of the lower edge exposed to the weather. Why do shingles get algae.

A copper strip at the top of the roof can prevent future roof algae. Thousands of roof on homes and other buildings suffer from black streaks. You may think you have roof algae when really you have moss mildew or mold. When it comes to preventing algae there are in fact several things homeowners and roofers can do.

Common algae that form on roof surfaces including asphalt shingles and roll roofing include the algae shown above and gleocapsa magma a species that generally appears black on the roof surface but under some lighting conditions even on the roof gleocapsa magma can appear as a blue green color as might other algae genera species. Gloeocapsa has the ability to form a protective darkly pigmented outer coating that shields the algae from damaging uv rays. Roof algae prevention tips. That way whenever it rains some of the metal molecules will wash down the roof and kill any algae trying to regain a foothold on your shingles.

Algae grow most often on wood and asphalt shingles or concrete tiles especially if they do not get a lot of sunlight. Although algae can be found on all types of roofing it tends to be most common on asphalt shingles. Algae spores are airborne.