Gutter Clean
Before 
After Spokane, WA — Licensed & Insured
Professional Roof Cleaning in Spokane
Moss and algae eat away at your shingles, trap moisture against the roof deck, and shorten the life of your roof. We clean Spokane roofs the right way — low-pressure soft-wash that removes growth without damaging the shingles underneath. Free estimates, guaranteed results.
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509 267 6458
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- Licensed & Insured
- Free Estimates
- 87 Five-Star Reviews
- Serving Spokane & Surrounding Areas
- 4.9 Average Rating
The problem
Why Spokane Roofs Get Moss
Spokane is one of the worst cities in the Pacific Northwest for roof moss, and the reasons come down to climate, geography, and tree cover. If you have lived here for more than a few years, you have almost certainly seen it — green patches spreading across north-facing slopes, black streaks running down the shingles, and thick moss mats taking hold in shaded areas.
Wet Winters and Persistent Moisture
Spokane receives roughly 16 to 17 inches of precipitation per year, but the problem is not total volume — it is duration. From October through May, the region experiences long stretches of overcast, damp weather with very little direct sunlight to dry things out. Roofs stay wet for days or weeks at a time. Moss thrives in exactly these conditions: consistent moisture above 40 degrees with limited evaporation.
North-Facing Slopes
In the northern hemisphere, north-facing roof slopes receive the least direct sunlight year-round. In Spokane, where winter sunlight is already limited, a north-facing roof plane may get no meaningful sun exposure for five or six months. That persistent shade keeps the surface damp, and moss colonises those areas first. Many Spokane homes show moss growth on the north side while the south side remains completely clean.
Tree Canopy and Shade
Spokane's mature neighbourhoods — South Hill, Five Mile, parts of the Valley — are defined by large Douglas fir, western red cedar, and pine trees. Those trees drop needles and leaves onto rooftops, which collect in the valleys and create organic compost that moss roots into. The canopy itself blocks sunlight and slows evaporation, creating a microclimate on your roof that is even wetter than the surrounding air. Homes in heavily treed areas often need roof cleaning every year or two rather than every three.
What moss does
The Damage Moss Causes to Your Roof
Moss is not just a cosmetic issue. Left untreated, it will shorten the life of your roof by years and can lead to leaks, wood rot, and expensive repairs. Here is what happens when moss takes hold.
Shingle Degradation
Asphalt shingles are coated with ceramic granules that protect the underlying asphalt from UV radiation. Moss grows between and under those granules, pushing them loose. As granules fall away, the raw asphalt is exposed to the sun, which dries it out and makes it brittle. You will often see granule loss in gutters and downspouts below a mossy roof — that is your roof literally wearing away.
Moisture Retention
A thick moss mat acts like a sponge. It absorbs rainwater and holds it against the roof surface long after the sky has cleared. That constant moisture works its way under shingles, through the underlayment, and eventually into the roof deck. Once the plywood or OSB deck starts to rot, the problem has moved from cosmetic to structural. Roof deck replacement means a full tear-off, which is one of the most expensive home repairs a Spokane homeowner can face.
Lifted Edges and Ice Damage
As moss grows, it pushes up the leading edges of shingles. Lifted shingles create gaps where wind-driven rain can enter. In winter, those gaps allow melting snow to flow underneath and refreeze at night, which makes the lifting worse and accelerates damage. Moss also expands when it freezes, prying shingles apart further with each freeze-thaw cycle. This is exactly the kind of damage that compounds over a Spokane winter and results in springtime leaks.
Gutter Blockage
Moss that breaks loose from the roof surface washes into gutters and downspouts, where it packs into dense mats that block drainage completely. Clogged gutters then overflow, dumping water along the foundation. So roof moss does not just damage the roof — it creates a chain reaction that affects your gutters, siding, and foundation. Keeping the roof clean is one of the most effective ways to protect the entire exterior system of your home.
Our method
Soft-Wash Roof Cleaning: Safe for Shingles
We clean roofs using a soft-wash method, which means professional-grade cleaning solutions applied at low pressure — roughly the output of a garden hose. There is no high-pressure wand, no blasting, and no risk of stripping shingle granules. The cleaning solution does the work, not the water pressure.
Why We Do Not Pressure Wash Roofs
Pressure washing is the wrong tool for roof cleaning. The high-pressure stream strips granules from asphalt shingles, cracks and displaces tiles, and forces water under flashing and into the underlayment. Every major shingle manufacturer — GAF, Owens Corning, CertainTeed — explicitly warns against pressure washing and will void warranties if it is detected. Despite this, many companies still use pressure washers because it is faster for them. It is faster because it damages the roof surface. We will not do that.
How Soft Washing Works
We apply a specially formulated cleaning solution that kills moss, algae, lichen, and the root systems they use to attach to your shingles. The solution is allowed to dwell on the surface — usually 15 to 30 minutes depending on the severity of growth — during which time the organic matter loosens and dies. We then rinse the roof with low-pressure water, washing away the dead material without disturbing the shingle surface. The result is a clean roof with its protective granule layer fully intact.
Preparation and Cleanup
Before we start, we cover all landscaping, garden beds, deck furniture, and walkways around the perimeter of your home with protective tarps. We pre-wet all vegetation to dilute any cleaning solution that contacts it. After the cleaning and rinse are complete, we collect any moss or debris that has come off the roof and leave the property exactly as we found it. If moss has washed into your gutters during the process, we can clean those out as well so your whole system starts fresh.
Maintenance
How Often Should You Clean Your Roof?
The right cleaning schedule depends on your home's specific exposure. In Spokane, most roofs need cleaning every two to three years, but some need it annually.
Factors that accelerate moss growth include north-facing roof planes, heavy tree canopy overhead, proximity to greenbelts or wooded areas, and low-pitch roofs that drain slowly. If your home has two or more of these factors, annual cleaning is a worthwhile investment. For more exposed homes with good sun, every three years is typically sufficient. We will evaluate your roof during the estimate visit and recommend a schedule.
- North-facing slopes retain moisture longer
- Tree canopy blocks sunlight and drops debris
- Wet winters create ideal moss conditions
- Moss lifts shingles and traps water
- Soft-wash cleaning protects shingle granules
- Preventive cleaning avoids costly roof replacement
Our work
Roof Cleaning Before and After
Moss removal results from Spokane homes. The soft-wash method removes years of growth without damaging shingles.
Before After Before After Algae Stain Treatment — Five Mile
Before After Full Roof Soft-Wash — Liberty Lake
See more of our work on the project gallery page.
What Spokane Customers Say About Our Roof Cleaning
“Our north-facing roof was covered in thick moss — you could barely see the shingles. They used the soft-wash method and it came out looking like new. No damage to the shingles at all. I was worried about pressure washing but they explained exactly why they do not use it. Very professional.”
“Had three large pines overhanging our roof and years of moss buildup. They killed everything, let it release, and washed it clean. The difference is incredible. They also cleaned out the gutters that were packed with moss debris. Will definitely have them back every couple years.”
“We were told by another company we needed a new roof because of the moss damage. Gutter Clean came out, cleaned it, and showed us the shingles were still in good shape underneath. Saved us thousands. Honest, thorough, and they left the yard spotless.”
Frequently Asked Questions About Roof Cleaning
How much does roof cleaning cost in Spokane?
Roof cleaning in Spokane typically ranges from $350 to $700 for a standard single-family home, depending on the roof size, pitch, and severity of moss growth. Smaller roofs and light algae treatments are on the lower end. Heavily moss-covered roofs with steep pitches may run higher. We provide free estimates so you know the exact cost before any work begins.
Is roof cleaning safe for asphalt shingles?
Yes, when done correctly. We use a soft-wash method that applies a professional-grade cleaning solution at low pressure — roughly the same pressure as a garden hose. This dissolves moss and algae without blasting off the protective granules on your shingles. High-pressure washing is the method that damages shingles, and we do not use it on roofs.
How often should I have my roof cleaned in Spokane?
Most Spokane homeowners benefit from a roof cleaning every two to three years. If your home has heavy tree canopy, sits on a north-facing slope, or is in a shaded neighbourhood like parts of South Hill or Five Mile, you may need annual cleaning. We will inspect your roof and recommend a schedule based on its specific conditions.
Why is pressure washing bad for roofs?
Pressure washing forces high-pressure water against asphalt shingles, which strips away the granule coating that protects the underlying asphalt from UV radiation. Once those granules are gone, shingles degrade rapidly and the roof needs premature replacement. Pressure washing can also force water under shingles and into the underlayment, causing leaks. Soft washing achieves the same clean results without any of this damage.
Will roof cleaning remove all the moss permanently?
Soft-wash cleaning removes all visible moss and algae and treats the surface to slow regrowth. In Spokane's climate, moss will eventually return because the environmental conditions — moisture, shade, and organic debris — are still present. A zinc or copper ridge strip can provide longer-term prevention. Most homeowners find that cleaning every two to three years keeps moss under control effectively.
Do you clean up the debris that falls from the roof?
Yes. We cover all landscaping, decks, and walkways around the perimeter of your home before we start. After the cleaning, we collect any moss or debris that has come off the roof and leave the property clean. We also clean gutters of any material that washes down during the process if you need it.
More questions? See the full FAQ page or call us directly.
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Roof Cleaning in Spokane Neighbourhoods
We clean roofs across Spokane and the surrounding Inland Northwest. Here are some of the areas we serve most frequently.
View all 25 service areas →Need Roof Cleaning in Spokane?
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