Roof Cleaning

What the black streaks actually are

Gloeocapsa magma. It is a blue-green algae that feeds on the limestone filler manufacturers blend into asphalt shingles, and it spreads by airborne spores — which is why one streaked roof on a street tends to become three.

It is not only cosmetic. The colony holds moisture against the shingle and darkens the surface, so the roof runs hotter and the mat underneath ages faster than it should.

Zero pressure, every time

A pressure washer will strip a shingle roof. The granules are the roof’s UV protection and its fire rating, and once they are in the gutter they are not coming back. Blasting a roof can take years off it in an afternoon.

We apply a shingle-safe solution at low volume, let it work, and rinse gently. The algae dies, the streaks lift, and the granules stay where the manufacturer put them.

Moss is a different problem

Moss roots into the seams between shingles and lifts their edges, which is how water finds its way underneath. It also takes longer to clear than algae — it dies on treatment but weathers off over the following weeks rather than rinsing away on the day.

If your roof has moss as well as streaking, we will say so in the quote and tell you what the roof will look like at the one-week and one-month mark.

Metal, tile and low-slope

Not every roof is asphalt. Metal, tile and low-slope roofs each need a different approach and a different rinse plan, mostly because of where the runoff goes. Send a photo and we will tell you which category yours falls in.