Maintenance
How to Safely Remove Moss From a Roof in the PNW
Moss treatment done right adds years to a roof. Done wrong, it strips the granules and voids your warranty. Here's the safe approach.
April 15, 2026·5 min read
Don't pressure-wash an asphalt roof
Pressure washing blasts off the granules that protect the asphalt from UV. It's the single fastest way to destroy a roof and void the manufacturer warranty.
The right approach
Brush off heavy moss pads gently with a soft brush, working downward so you don't lift shingles. Then apply a zinc-sulfate or potassium-salt based moss treatment per the manufacturer instructions.
Zinc strips installed at the ridge will keep new moss from re-establishing for years.
When to call a professional
If moss has been there long enough to lift shingles, expose underlayment, or rot the decking, treatment alone won't fix it — schedule an inspection.