Professional Roof Treatment
& Moss Removal in Seattle
Protect your most important investment. Our soft wash roof treatment removes moss, algae, and lichen without damaging shingles — extending your roof's life by years.
Seattle's Roof Moss Problem — And How We Solve It
In the Pacific Northwest, roof moss isn't just cosmetic. It's a serious threat to your home's most critical component. Seattle and Eastside roofs face persistent moss, algae, and lichen growth due to our combination of heavy rainfall, mild temperatures, and significant tree canopy — creating near-perfect conditions for biological growth year-round.
Untreated roof moss can reduce your roof's lifespan by 10+ years — lifting shingles, retaining moisture, and accelerating deterioration from the inside out. Professional treatment is one of the highest-value maintenance investments a PNW homeowner can make.
Why We Only Use Soft Wash on Roofs
Many companies use pressure washers on roofs — this is a serious mistake. High-pressure water strips granules from asphalt shingles (reducing their UV protection), forces water under cedar shakes, and can crack tile roofing. It also voids most roofing manufacturer warranties.
Our soft wash method uses low pressure and specialized cleaning chemistry to kill biological growth at the root level. The results last 2–4 times longer than pressure washing, and your roof remains completely undamaged.
What Our Roof Treatment Includes
Every roof treatment is a careful, methodical process built to remove growth thoroughly without ever putting your shingles at risk.
Full Roof Inspection & Condition Assessment
We start by assessing your roof's material, slope, and condition — identifying problem areas in valleys, ridges, and north-facing sections where moss and lichen concentrate.
Safe Soft Wash Application
We apply a biodegradable moss-killing treatment across the entire roof surface using low pressure only — never high-pressure water that could strip granules or force water under shingles.
Landscaping Protection & Gutter Clearing
We protect surrounding landscaping throughout the job and clear debris from gutters and downspouts so runoff drains cleanly after treatment.
Post-Treatment Walkthrough & Report
We walk the property with you and provide a condition report — including prevention advice tailored to your roof, like trees to trim back and gutters to keep clear.
Roof Types We Treat
Our soft wash method is safe and effective across every common Pacific Northwest roofing material:
Asphalt Architectural Shingles
The most common roof in the Seattle area. Soft washing removes black streaks and moss without stripping the protective granules.
Cedar Shake & Shingle
Cedar is especially vulnerable to moisture and needs gentle treatment. Our low-pressure method cleans without forcing water under shakes.
Tile Roofing (Clay & Concrete)
Tile can crack under pressure washing. We treat clay and concrete tile safely, preserving both the tile and its finish.
Metal Roofing
We remove oxidation, streaking, and biological growth from metal roofs while protecting coatings and seams.
Low-Slope & Flat Commercial
Commercial and low-slope roofing treated to remove growth and debris that accelerates membrane deterioration.
Heavy Moss & North-Facing Roofs
Shaded, tree-covered, and north-facing roofs accumulate the most growth. We give these areas extra attention and pre-treatment.
Why Seattle Homeowners Trust Our Roof Treatment
Shingle-Safe Soft Wash Only
We never pressure wash a roof. Our method is the manufacturer-approved way to clean without voiding your warranty.
Root-Level Moss Kill
We kill moss, algae, and lichen at the root and spore level — so results last 2–3 years, not a few months.
Licensed & Fully Insured
Full liability insurance and the safety training to work steep and multi-story roofs across the Eastside.
Eco-Friendly & Landscape-Safe
Biodegradable treatments that protect your landscaping, pets, and the Puget Sound watershed.
Longer-Lasting Results
By killing growth at the root instead of just removing the surface, our treatment keeps roofs cleaner for years — with prevention advice to extend it further.
100% Satisfaction Guarantee
A full post-treatment walkthrough and condition report on every job. We don't leave until it's right.
How Much Does Roof Treatment Cost in Seattle?
Roof treatment pricing depends on your roof's size, pitch, material, and the severity of moss buildup. We provide transparent, itemized quotes with no day-of surprises — and bundling with a house wash or gutter cleaning is almost always more cost-effective than booking separately.
Roof Size & Pitch
Larger and steeper roofs require more time, material, and safety setup. We price accurately before any work begins.
Moss Severity
Heavy, long-neglected growth needs additional pre-treatment and dwell time. We account for this upfront in your quote.
Service Combinations
Adding gutter clearing, a house wash, or an Annual Power Plan lowers your per-service cost. Ask about combination discounts.
The fastest way to an accurate price is a free quote. We respond within 24 hours — often same day.
Frequently Asked Questions
Will roof treatment damage my shingles or void my warranty?
No — our soft wash roof treatment is specifically designed to be safe on all roofing materials including asphalt shingles, tile, and cedar shake. We never use high-pressure washing on roofs. Many roofing manufacturers actually recommend soft washing as the only approved cleaning method to avoid voiding warranties.
How often should I treat my roof for moss in Seattle?
In the Pacific Northwest climate, we recommend roof treatment every 1–2 years. Homes with heavy tree coverage or significant north-facing roof exposure may need annual treatment. Cedar shake roofs typically require more frequent attention than asphalt or tile.
Will the moss come back after treatment?
Soft wash treatment kills moss, algae, and lichen at the root and spore level, significantly delaying regrowth. Most Seattle and Eastside homes see 2–3 years before meaningful regrowth occurs. Keeping trees trimmed back and gutters clear helps extend the interval between treatments.
Can you treat a steep or multi-story roof safely?
Yes — our team has the proper safety equipment, training, and insurance to work on steep and multi-story roofs throughout the Seattle and Eastside area. Safety is our top priority on every job.
Have a question we didn't answer? Call (425) 298-7041 or submit a quote request — we respond within 24 hours.
Preventive Roof Care & Related Services
The most cost-effective approach to roof moss is prevention. Bundle roof treatment into a year-round plan, or add a related service to the same visit.
Protect Your Roof Before the Next Wet Season
Get a free, no-obligation roof treatment quote for your Seattle or Eastside home. We respond within 24 hours — often same day — and serve Seattle, Bellevue, Kirkland, Redmond, Sammamish, Bothell, Issaquah, Mercer Island, and surrounding communities.
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