08/31/2026
Danville roofs sit under some of the best tree cover in the Tri-Valley, and that shade comes at a cost. Japanese maples, valley oaks and mature landscaping drop leaf litter into roof valleys and along the gutter line, where it packs down and holds moisture long after the surface has dried. Add the marine fog that rolls in off the Bay overnight and the cool morning air coming down out of the Mount Diablo foothills, and north-facing slopes can stay damp well into the day. That standing moisture is what moss, lichen and algae need to take hold. Once they do, they root into the granule surface of the shingle and spread along the courses, trapping even more debris and slowing drainage toward the gutter.
The instinct is to climb up with a pressure washer and blast it off, and that is where composition roofs get destroyed. Shingles are protected by a mineral granule layer, and high pressure strips those granules in a single pass, exposing the asphalt mat underneath to UV and shortening the life of the roof by years. Pressure aimed uphill also drives water under the shingle courses and into the underlayment, creating leaks that do not show up until the first real storm. Scraping and wire brushing tears the mat outright, and most manufacturer warranties are voided the moment a pressure washer touches the surface. There is also the obvious risk of working a wet, sloped roof without proper fall protection.
PPWPM cleans composition roofs with a low-pressure soft wash system, never a pressure washer. We hand-clear the heavy debris from valleys, roof-to-wall transitions and the gutter line first, then apply a roof-safe treatment that kills moss, lichen and algae at the root and lifts organic staining without disturbing a single granule. The roof is rinsed at low volume so water moves the way the roof was designed to shed it, and we verify the gutters and downspouts are flowing clear before we pack up. With 12 years in business and hundreds of five-star reviews across the Tri-Valley, our crews know how these roofs age under local tree cover. Homeowners who want to stay ahead of regrowth can enroll in our HomeGuard Maintenance Membership, which keeps the roof, gutters and exterior surfaces on a scheduled rotation instead of waiting for the moss to come back.
Serving San Ramon, Danville, Alamo, Blackhawk, Diablo, Walnut Creek and surrounding areas.
Call 925-633-4342 or visit PPWPM.com for a free estimate.