Roof Moss Removal
the Grays Harbor way

Can you pressure wash a roof?

You shouldn't. High pressure strips the protective granules off composition shingles, drives water under the laps, and can void a roof warranty. Roofs get a soft wash and moss treatment: the solution kills the moss and algae at the root, the dead growth is brushed or rinsed away at low pressure, and a preventive treatment slows it from coming back.

Why moss comes back — and what actually works

Moss spores are in the air year-round on the coast; shade and moisture do the rest. Scraping alone leaves roots and comes back in a season. Treatment kills the roots. The combination that lasts is: kill it, remove the dead material gently, treat again on a schedule, and keep the big branches trimmed back off the roof. On most roofs here, a treatment every one to two years keeps it under control.

Roof types

• Composition / asphalt shingle — the most common in Aberdeen and Hoquiam, and the most vulnerable to pressure. Soft wash only.
• Metal — algae and moss come off well; care taken at seams and fasteners.
• Cedar shake — gentle treatment; heavy moss on shake takes more than one visit.
• Tile — walked carefully or cleaned from the edge to avoid breakage.

What about my gutters?

The dead moss has to go somewhere. Gutters get cleared of what comes off the roof as part of the job, and downspouts get flushed so the first storm doesn't back up.

How much does roof moss removal cost?

Priced on roof size, pitch, and how thick the moss is. A one-story ranch with light moss is a quick job; a steep two-story with inches of moss is a day. Every roof gets a free assessment — photos from the ground are often enough to quote. See the pricing guide.