The Pacific Northwest's climate — wet winters, mild temperatures, and significant tree canopy — creates specific challenges for roof maintenance. Here's what Southwest Washington homeowners should stay on top of.
This is the defining roof maintenance challenge in the Pacific Northwest. The combination of moisture, mild temperatures, and shade from Douglas firs and other conifers creates ideal conditions for moss and algae growth. Left untreated, moss can significantly shorten a roof's lifespan.
Annual inspection and treatment — applying a biocide and removing existing growth — is the standard recommendation. Zinc strips along the ridge can help slow regrowth between treatments.
Fir needles, leaves, and other organic debris accumulate on roofs and in valleys. This debris retains moisture, promotes moss growth, and can block drainage. Keeping the roof clear of debris — particularly in valleys and around penetrations — is an important part of roof maintenance.
Gutters clogged with debris can't drain properly. Water backs up, potentially infiltrating under shingles at the eaves. In winter, clogged gutters can contribute to ice dam formation. Annual gutter cleaning — ideally in late fall after the leaves have dropped — is essential in the Pacific Northwest.
After significant wind events, it's worth checking for missing or damaged shingles. Missing shingles expose the roof deck to water infiltration. Damaged shingles — lifted, cracked, or with missing granules — should be replaced promptly.
Flashing around chimneys, skylights, and roof penetrations is a common source of leaks. Annual inspection — looking for lifted, cracked, or corroded flashing — can catch problems before they cause interior water damage.
Horizon Chimney Sweep serves Vancouver, Woodland, and all of Southwest Washington. Licensed, locally owned, and honest about what you need.