Does Roof Soft Washing Void Your Shingle Warranty?
What the shingle makers actually say, and the one method they all warn against.
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The short answer
Low-pressure soft washing with a diluted bleach-based solution is the cleaning method shingle makers themselves describe. ARMA and GAF both warn against pressure washing shingles because it knocks off granules. Warranty terms vary by manufacturer and product, so read your own warranty or ask the maker before any cleaning. We'll tell you exactly what we use.
If the north side of your roof has black streaks, you've probably wondered whether cleaning it could cost you your shingle warranty. It's a fair question, and the people who make the shingles have answered most of it in writing.
I'm Anthony. A Team Contracting is a family-owned crew out of Tipp City, and we soft wash roofs across the Miami Valley. We never put a pressure washer on shingles. Here's what the manufacturers say, and what I'd check before anyone touches your roof, including us.
The short answer
Soft washing is the method the shingle industry itself describes for removing algae. What the manufacturers warn against is pressure washing, scrubbing, and using chemicals they haven't approved. But warranties are written by each manufacturer for each product line. We can't promise what your specific warranty says, so the right move is to read it or call the maker. That takes ten minutes and settles it.
What GAF and ARMA actually say
ARMA, the asphalt roofing manufacturers' trade group
The Asphalt Roofing Manufacturers Association says algae discoloration "may be lightened by applying a solution of liquid household bleach (sodium hypochlorite) and water," that the solution "should be gently dispersed on the roofing surface," and that "other cleaning chemicals or methods should not be used without the approval of the shingle manufacturer." ARMA also encourages using professionals, because the process makes the roof slippery.
Then, in capital letters: "DO NOT use a power washer or any type of brush or broom to clean algae from the roof surface." ARMA says high-pressure washing is likely to damage asphalt roofing.
GAF, a major shingle maker
GAF's technical bulletin on algae staining (TAB-R-102) recommends a mix of water, bleach and trisodium phosphate (or a phosphate-free substitute), applied, left to sit for up to 20 minutes, and rinsed with low-pressure water, with shrubs protected below. Under "What NOT to do," it says not to power wash shingles because it "may dislodge granules, which can lead to premature shingle failure."
That's the core of it. Both point to a low-pressure, bleach-based clean. Both say no pressure washer.
Why pressure washing is the real risk
Asphalt shingles are covered in mineral granules. They shield the asphalt from UV and weather. High pressure strips them off. The roof looks clean that afternoon and then ages early, and loose granules end up in your gutters.
So if someone offers to "power wash" your roof, that's the method the manufacturers specifically warn against. Soft wash for roofs and siding. Pressure wash for concrete. If you only remember one rule, that's the one.
How to check your own warranty
- Find the paperwork. Your roofer should have given you the manufacturer's limited warranty and, for some products, a registration.
- Look for a maintenance or cleaning section. Note any approved cleaning method or chemicals, and any exclusions for "improper maintenance."
- If it's unclear, call the manufacturer. Ask: "Is a low-pressure sodium hypochlorite soft wash, rinsed with low-pressure water, acceptable on my shingles?"
- Ask your cleaner what they use. A real roof cleaner will tell you the chemical, the dilution approach, and how they rinse. We do.
How we soft wash a roof
- No pressure washer on shingles, ever
- We wet down and cover plantings before anything goes on the roof, and rinse the beds after
- A properly diluted sodium hypochlorite solution, applied at low pressure
- We let it work, then rinse gently
- No scrubbing or brooms on the shingle surface
The black streaks are algae called Gloeocapsa magma. They have to be killed, not blasted. Our own streak warranty is separate from your shingle warranty: 24 months on organic streaks. See roof cleaning in Dayton or roof cleaning in Tipp City for the full service, and how to remove black streaks from a roof for more on the algae itself.
Roof + gutter offer
Roof clean and sealcoat, with free gutter cleaning, for $1,500 on an average two-plane roof. Bigger or more complex roofs get quoted separately. A roof soft wash on its own runs $400–$800 for a typical asphalt shingle roof on our pricing page.
Algae-resistant shingles have their own warranty
Some newer shingles carry a separate algae warranty. GAF, for example, offers StainGuard algae protection limited warranties on qualifying products sold in packages bearing the StainGuard logos. Under that warranty, if covered shingles show pronounced blue-green algae discoloration during the coverage period, GAF's remedy can be the reasonable cost of commercially cleaning them. If your roof is newer and already streaking, check whether that coverage applies before paying for a cleaning.
Book a roof soft wash
Property managers and HOA boards: the same rule applies at every building, and we're glad to put our method in writing for your files. Homeowners: snap a photo of the streaked side and get a price, or call or text me at (937) 777-9093. I call back the same day, Monday through Saturday.
Frequently Asked
The questions we get every week.
Get Your Roof Streak-Free the Right Way
Snap a pic of the streaked side of the roof. We'll tell you exactly what we'd use.
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