Roof Algae & Lichen Removal in Shoreline, WA

Not everything green — or black — on your roof is moss. Algae streaks and crusty lichen need different treatment than moss, and using the wrong approach wastes your money. We identify what's actually growing and treat each correctly.

📞 Call (206) 555-0199

Know what you're fighting

Moss vs. Algae vs. Lichen: Why It Matters

Black streaks (gloeocapsa magma algae): the most common roof discoloration in Shoreline. This blue-green algae feeds on the limestone filler in asphalt shingles, spreading in streaks down the roof. It's mostly cosmetic at first but accelerates shingle aging — and it makes your roof look terrible.

Lichen: the crusty, pale-green or white patches that look like they're painted on. Lichen bonds tightly to the shingle surface — aggressive scrubbing to remove it pulls granules off with it. It needs chemical treatment and patience, not elbow grease.

Moss: the thick, spongy green mats. Different root structure, different removal approach — manual lifting plus treatment.

Why this matters: a company that treats everything like moss will scrub lichen aggressively (damaging shingles) or ignore algae streaks (leaving your roof looking dirty). Correct identification is the first step of a proper job.

Our Approach to Each

Algae streaks: soft wash with algaecide solution — streaks fade over days to weeks, roots killed
Lichen: targeted chemical treatment, then gentle removal once the bond breaks — never aggressive scraping
Moss: manual removal of mats, then soft wash and prevention treatment
Mixed growth: common in Shoreline shade — we sequence treatments correctly
Full prevention treatment after cleaning, whatever the growth type

FAQ

Algae & Lichen Questions

Slowly, yes. The algae feeds on limestone in your shingles and holds moisture against the surface, accelerating granule loss. It's also the thing insurers and HOAs notice first. Treatment is straightforward — don't ignore it for years.

Yes, with the right method: chemical treatment first to break lichen's bond, then gentle removal. Scrubbing live lichen off is what causes damage. Patience beats pressure.

Algae spores are everywhere in our damp air, so prevention treatment is essential. With treatment, expect 2+ years clear. Without it, streaks return within a year on shaded slopes.

Streaks, Spots, or Mats — We'll Sort It

Free inspection identifies exactly what's growing on your roof.

📞 Call (206) 555-0199