Roofing professionals in the Pacific Northwest understand the persistent challenge that moss and algae present due to the region’s unique climate. With high moisture levels and frequent rainfall, roof maintenance is essential to preventing the damp conditions that foster moss and algae growth. Guardian Roofing, Gutters & Insulation, a trusted name in roofing and home services, has developed specialized strategies to help property owners maintain the integrity of their roofs.
“Roofs retain moisture, particularly in shaded areas, allowing moss to take root,” explains Matt Swanson from Guardian Roofing. “Unlike hotter regions where sunlight can dry and kill moss, the Pacific Northwest’s cooler temperatures keep surfaces damp longer. Tall evergreen trees and overcast skies mean many roofs receive limited direct sunlight, preventing them from drying out. North-facing and heavily shaded areas are especially vulnerable to moss and algae accumulation.”
When conducting roof inspections, Guardian’s experts assess critical design factors that contribute to moisture retention. Low-pitch roofs tend to hold water longer, accelerating moss growth. Additionally, poor drainage and clogged gutters exacerbate the problem by trapping excess moisture on the roof’s surface.
“The structural and aesthetic damage caused by moss and algae can significantly shorten a roof’s lifespan,” continues Swanson. “Moss roots can lift shingles, leading to leaks and water damage, while algae create dark streaks that not only reduce curb appeal but may also impact home value. DIY removal can be hazardous due to slippery conditions and roof height, which is why we always recommend a professional inspection in the spring to mitigate potential problems before they worsen.”
Guardian Roofing’s comprehensive assessment process includes evaluating moss and algae growth, checking for roof damage such as lifted shingles, leaks, degranulation, and clogged gutters. Based on the roof’s material and condition, a customized treatment plan is then implemented to restore and protect the roofing system.
“The best way to prevent moss is through consistent maintenance, keeping roofs free of dirt and debris,” advises Swanson. “We recommend an annual full roof inspection and moss treatment. However, homes in heavily wooded or shaded areas may require cleaning every six months. The team at Guardian is committed to helping homeowners in the Pacific Northwest preserve their roofs, ensuring durability and peace of mind year-round.”
By staying proactive with regular inspections and treatments, roofing professionals can help homeowners combat moss and algae, extending the longevity of their roofing systems in this moisture-rich environment.
About Guardian Roofing, LLC
Founded in 2005, Guardian Roofing, LLC is an award-winning professional roofing contractor in the Portland and Seattle markets including the Washington State counties of King, Pierce, Snohomish, Kitsap, Clark, and Thurston; and now Oregon counties of Marion, Washington, Multnomah, Clackamas and Yamhill, serving the entire Pacific Northwest.
Founders Lori and Matt Swanson have more than 60 years of combined roofing experience and employ a team of more than 100 skilled and professionally certified craftsmen who assist customers with their roof, gutter, attic, masonry, and skylight needs. λ
