Black Algae On Roof Shingles

Here s why algae grows on roofs.

Black algae on roof shingles.

To save money most shingle manufacturers have switched to shingles containing asphalt but mostly made up of fillers such as fiberglass and crushed limestone which encourages the growth of algae. Black stains on asphalt shingle roof caused by algae growth. The algae feed on the limestone in shingles. Roof algae generally have a black green hue.

The streaks look like mold but they re actually algae colonies that form in your shingles and feed on moisture and the limestone filler agents in the shingles. Black streaks on the north and west facing and shaded areas of your asphalt shingled roof can really wreck the appearance of your home. Algae grow most often on wood and asphalt shingles or concrete tiles especially if they do not get a lot of sunlight. I am really disappointed the treated shingles didn t work.

I covered our asphalt shingle roof about five years ago with white 50 year guaranteed shingles that had algae prevention treatment but now the entire north side of our roof is black with algae i bought the shingles from lowe s in marianna florida. The most common class of roof algae is gloeocapsa magma a bacterium that eats water and expels oxygen. As the blue green algae accumulate they develop a dark hardened outer coating which results in the black stains you see. Here we discuss the causes of algae growth on roof shingles the effects of these conditions and how to cure or prevent algae formation on roofs.

The black streaks are also known as black algae or roof mold. If you live in a humid area of the country you ve probably seen unsightly dark streaks on asphalt shingle roofs. Algae stains on roofs. Technically the black streaks on roofs are a form of algae known as gloeocapsa magma.

Causes cures of black brown or green algae staining on roof surfaces. Mix up oxygen based cleaner with water in a five gallon bucket following the instructions. The algae will worsen and become more noticeable each year trapping moisture and causing premature shingle aging and granule loss.