Soft-wash roof cleaning. The black streaks come off. The shingles stay on.

No, soft washing is the method the Asphalt Roofing Manufacturers Association (ARMA) recommends. High-pressure washing of asphalt shingles is what damages them. Correctly diluted SH with a surfactant, applied at low pressure, kills the algae without touching the granules.

Gloeocapsa loves shade and moisture. The north-facing slope (and the west-facing in some San Diego microclimates) stays damper longer, so that's where the colony takes hold. It spreads slowly from there. That's also why coastal homes get streaks faster, marine layer fog feeds it.

Typically 4 to 6 years before streaks are visible again. We can extend that significantly by installing zinc or copper strips near the ridge, rainwater picks up metal ions as it flows down, which inhibits regrowth. We'll include a strip recommendation on the quote if your roof benefits.

Yes. Tile (clay or concrete) soft-washes well and we're careful about where we step to avoid cracking. Metal roofs take a low-pressure rinse after chemistry, high pressure can strip the Kynar or acrylic coating and cause premature rust, so we never push it.

We flush the gutters after the wash so algae die-off does not clog them. If you want full gutter cleaning at the same visit, we add that for less than booking it separately, see the window and gutter page.