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Roof cleaning & moss removal
Roof Cleaning & Moss Removal in Seattle, WA
Moss loves a shaded Seattle roof. We clear it off gently, clean out the gutters and check the shingles underneath, so your roof lasts as long as it should.
Left alone for a few seasons, that means water getting under the shingles, rotting decking and leaks that show up in the middle of winter. Cleaning it off early is far cheaper than repairing what it leaves behind.
Moss lifts shingle edges and lets wind-driven rain underneath
Careful, by hand and done in a way that protects the roof instead of wearing it out.
01 / 05
01
Look first
We check the roof before we touch it, so any lifted or damaged shingles are found and photographed.
02
Gentle removal
Moss is brushed and scraped off by hand. No pressure washer: it strips the granules and pushes water under the shingles.
03
Treat
A moss and algae treatment slows regrowth on the shaded sections where it comes back fastest.
04
Gutters
Gutters and downspouts are cleared of the moss and needles so water drains the way it should.
05
Report
You get before and after photos and a note on anything that needs a repair.
Signs
Signs your roof needs cleaning
Green or fuzzy patches
Moss usually starts on the shaded side and along the edges.
Overflowing gutters
Moss and needles washing down block the gutters and downspouts.
Dark streaks
Black or green streaks are algae eating into the shingle surface.
Branches overhead
Trees keep the roof damp and shaded, and drop debris that feeds moss.
Treatment
Roof moss treatment and roof algae removal
Taking the moss off is half the job. On a shaded Puget Sound roof the spores are still there, so after cleaning we apply a moss and algae treatment that slows regrowth, with the most attention on the north side and under trees, where it comes back first.
The black streaks you see running down many Seattle roofs are algae, not dirt. They feed on the shingle surface and hold moisture. The same treatment takes care of them over the following weeks, without scrubbing the granules off.
Roof and gutter cleaning go together: everything that comes off the roof ends up in the gutters, so every job includes clearing gutters and downspouts so the next storm drains properly.
Cost
What affects roof cleaning and moss treatment cost
The size and pitch of the roof, and how easy it is to reach safely
How much moss there is, and how long it has been growing
The roofing material: cedar shake, shingle and tile each need a different approach
Whether the gutters and downspouts are packed solid
Any shingles or flashing the moss has already damaged
Our promise
Cleaning, not replacing
A good roof cleaning company should tell you this first: a mossy roof doesn’t mean you need a new roof. Most roofs only need a careful cleaning, a treatment and maybe a few shingles replaced where the moss has done damage.
If anything under the moss needs more than that, we’ll show you the photos and tell you straight.
FAQs
Roof cleaning questions
Straight answers to the questions we hear most. Don’t see yours? Give us a call.
Not for shingles, so we don’t do it. Pressure washing strips the protective granules off shingles and can force water underneath. We remove moss by hand and treat the roof instead.
How often should a Seattle roof be cleaned?
Most roofs around Puget Sound do well with a cleaning every one to two years, more often under heavy tree cover. A yearly treatment slows moss coming back.
When is the best time of year to remove moss from a roof?
A dry spell is best, usually late spring through early fall around Seattle: the moss comes off cleanly and the roof is safer to work on. A treatment in early fall, before the rains settle in, slows regrowth through the winter.
Do you clean gutters too?
Yes. Gutters and downspouts are cleared as part of every roof cleaning, since that is where the moss and needles end up.
How do I remove moss from my roof myself?
Carefully, and only in dry weather: roofs are slippery when they are mossy and wet, and the wrong tools damage the shingles. If you want to do it yourself, read our guide to roof moss removal first, or call us for a free quote.
Whether it’s a stubborn leak, storm damage and an insurance claim, or a brand-new roof, The Ranier Roof Doctor is here to help. Tell us about your project and we’ll call you back to schedule a free estimate.
