Moss loves Vancouver roofs. Wet winters and big trees keep shingles damp for months. But blasting a roof with a pressure washer does more harm than good.
What high pressure does to shingles
Asphalt shingles are covered in small granules that protect them from sun and rain. High pressure knocks those granules off, which shortens the life of the roof. It can also force water up under the shingles. Many shingle makers warn against pressure-washing for exactly this reason.
What we do instead
- Hand-remove heavy moss with soft tools, working downhill with the shingles.
- Apply a low-pressure treatment that kills the remaining moss and algae at the root.
- Let time and rain do the rest. Dead moss loosens and washes off over the next few weeks.
- Clear the gutters after, so loosened moss doesn't clog them.
What about the black streaks?
Those dark streaks are usually algae, not dirt. The same gentle treatment removes them without scrubbing.
Best time to treat
Early fall, before the long rains, is ideal. A yearly treatment keeps moss from ever getting thick again.
Want a quick quote?
Text us a few photos and we'll tell you honestly what it needs.
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