Best Roof Cleaners for Black Streaks & Moss (2026)

Cleaner Types, Safe Application & Keeping the Roof Clean

The black streaks running down asphalt shingles are a blue-green algae, not dirt, and the method you choose to remove them decides whether the roof gains years or loses them. Sodium hypochlorite blends kill algae, moss and lichen on contact and are what soft-wash contractors use; sodium hydroxide blends are gentler on planting but slower; zinc and copper strips at the ridge prevent regrowth rather than clean. Pressure washing strips the granules that protect the asphalt and voids most shingle warranties. This guide covers the three cleaner families, a safe low-pressure application sequence, dwell and rinse timing, plant protection, ladder safety and how long results realistically last.