How to identify and remove mold on your roof

You've noticed unusual spots on your roof? It might be mold! Here's how to recognize and eliminate it once and for all.

Recognizing the Signs of Mold on Your Roof

Mold often appears as black spots or streaks covered with a brownish moss. If you have it, it's likely to be more prolific on the less sunny and more humid slopes. If you also have it in your attic, your roof is probably not waterproof (see the 3 places to check to determine if it's waterproof).

The Culprit? Blue-Green Algae

The cause of mold on your roof is actually blue-green algae, producing a form of cyanobacteria called "Gloeocapsa magma."

Its presence and growth are due to the presence of limestone powder in the asphalt of your roof shingles. Blue-green algae feed on this powder, clinging to the ceramic granules and spreading with rainwater.

How to Clean Your Roof from Mold?

Since blue-green algae on your roof are microplants that root themselves in the shingles, it's crucial to destroy them at the source: a simple wash will only remove the moss, not the root. By doing so, blue-green algae would flourish again in the same season.

To eradicate them, get a biodegradable antifungal product from a specialized store and spray it on the plants. This way, you'll destroy the root.

Our professional roofers also use these products and are qualified to rid you of blue-green algae. Contact them if you need their services or advice! Contactez-les if you need their services or advice!