Roof Cleaning & Moss Removal

Washington's wet climate means moss and algae establish on composition shingles, tile, and metal roofs within 18–24 months of installation. Left untreated, moss lifts shingle edges, holds water against the underlayment, and accelerates granule loss. AWP Exterior Cleaning uses soft washing — low-pressure application of cleaning solution followed by manual brushing and rinsing. High-pressure washing tears granules off shingles and voids most manufacturer warranties.

The process kills moss and lichen at the root structure, then the crew hand-brushes to remove dead growth without damaging the roof surface. Any company applying moss treatment in Washington must carry a commercial pesticide applicator license from the Washington State Department of Agriculture. AWP's technicians hold licenses in both Washington and Oregon, apply EPA-registered products, document application rates, and follow state re-entry intervals.

“High-pressure washing tears granules off shingles and voids most manufacturer warranties.”

Most residential roofs across Greater Clark County take 3–5 hours to clean depending on pitch, square footage, and moss density. Roofs with heavy buildup or multiple valleys take longer. The crew removes all debris from gutters and downspouts during the process, and rinses landscaping before and after to protect plants.

AWP recommends cleaning every 1–2 years in the Portland-the area area. Homes under heavy tree cover or north-facing roofs may need annual service. Waiting longer than two years usually means heavier moss establishment and longer treatment time. The crew provides before-and-after photos for every job, and if you're not satisfied with the results, let them know within 48 hours — they'll come back to address the issue at no charge.