Does Roof Washing Void Your Warranty? What NC Homeowners Need to Know
- Nick Corbelli
- Mar 5
- 4 min read
Professional soft washing does not void your roof warranty. Pressure washing almost certainly will. The three largest shingle manufacturers in North America, GAF, Owens Corning, and CertainTeed, all warn against pressure washing asphalt shingles. High-pressure water strips the protective granules off your shingles, forces water under the tabs, and gives the manufacturer a reason to deny your claim. Soft washing, which uses low-pressure chemical treatment, is the manufacturer-approved method.
Why Pressure Washing Voids Most Roof Warranties
Asphalt shingles are covered in small ceramic granules that protect the underlying material from UV rays and weather. A pressure washer operating at 2,000 to 4,000 PSI blasts those granules right off the surface. Once those granules are gone, the shingle dries out, cracks, and fails years early.
Every major shingle manufacturer states this clearly in their warranty documents. Damage caused by improper cleaning methods, including pressure washing, is not covered. That means if your shingles fail after being pressure washed, the manufacturer will not pay for replacement, even if the shingles are only five years old. According to Angi's guide on roof warranty violations, improper cleaning is one of the most common warranty mistakes homeowners make.
Homeowners in Landfall and across Wilmington sometimes hire companies that show up with a pressure washer and no knowledge of warranty guidelines. One bad cleaning can cost you decades of warranty coverage on a roof that cost $10,000 to $25,000 to install.
What the Major Manufacturers Actually Say
Here is what the three largest shingle manufacturers say about roof cleaning and warranty coverage, based on asphalt shingle warranty guidelines and published manufacturer documentation.
Manufacturer | Pressure Washing | Soft Washing | Warranty Warning |
GAF | Not recommended, voids warranty | Approved at low pressure | Damage from improper cleaning not covered |
Owens Corning | Not recommended, voids warranty | Approved with proper solutions | Damage from improper maintenance not covered |
CertainTeed | Not recommended, voids warranty | Approved at low pressure | Damage from improper cleaning not covered |
All three manufacturers agree: soft washing with a low-pressure chemical treatment is the only approved method for cleaning asphalt shingle roofs.
How Soft Washing Protects Your Warranty
Soft washing operates at 60 to 100 PSI, roughly the pressure of a garden hose. Instead of blasting dirt and algae off with force, the cleaning solution does the work. A diluted sodium hypochlorite solution kills algae, mold, and mildew at the root. The crew sprays the solution, lets it dwell, and rinses gently with low-pressure water directed downward along the shingles.
This method:
Preserves your shingle granules so your roof maintains its UV protection
Kills Gloeocapsa magma (the cyanobacterium that causes black roof streaks) at the source
Follows manufacturer guidelines so your warranty stays intact
Extends your roof's lifespan by removing organisms that feed on shingle material
At Window Cleaning Wizards, we soft wash every roof in Wilmington, Leland, and surrounding communities using this exact process. No one walks on your roof. No pressure washer touches your shingles. If you are concerned about how salt air damages your roof and siding over time, regular soft washing is the best defense.
When Your Roof Actually Needs Cleaning
Not every roof needs cleaning every year. Here are the signs that your roof is ready for a soft wash:
Dark streaks or stains running down from the ridge line
Green patches on shaded sections or north-facing slopes
Moss growth in areas that stay damp, especially under overhanging branches
Your HOA sent a notice about roof appearance
Most homeowners in Waterford and Hampstead benefit from roof washing every two to three years. Homes closer to the coast near Carolina Beach or near heavy tree cover may need cleaning more often because humidity and shade accelerate algae growth.
If your roof still looks clean and shows no signs of algae or moss, leave it alone.
Unnecessary cleaning is unnecessary risk. For more on choosing between soft washing and pressure washing for your roof, read our full guide.
Frequently Asked Questions
Does soft washing a roof void the manufacturer's warranty?
No. Soft washing uses low-pressure application at 60 to 100 PSI with a cleaning solution that kills algae and mold. This method follows the guidelines set by GAF, Owens Corning, and CertainTeed. As long as the cleaning is done properly, your warranty remains valid.
Will pressure washing my roof void the warranty in North Carolina?
Yes. All three major shingle manufacturers state that damage from pressure washing or improper cleaning is not covered under warranty. Pressure washing strips protective granules and can force water under the shingle tabs, causing hidden leaks and premature failure.
How much does roof washing cost in Wilmington NC?
Professional soft wash roof cleaning in the Wilmington area typically costs $300 to $600 for a standard single-story home. Two-story homes and larger roofs run $500 to $900. This should include the full chemical treatment, proper rinsing, and plant protection.
How do I know if my roof cleaner is using soft wash and not pressure washing?
Ask directly. A reputable company will tell you their PSI range (should be under 500), the cleaning solution they use, and confirm that no one walks on your shingles. If a company shows up with a commercial pressure washer and no chemical application setup, that is a red flag.
Can I clean my roof myself to avoid voiding the warranty?
You can, but it is risky. Walking on a roof, especially one with algae, is dangerous. Mixing and applying sodium hypochlorite requires proper equipment and safety gear. Most homeowners are better served by hiring a professional crew that carries liability insurance and knows the manufacturer guidelines.
Keep Your Roof Clean and Your Warranty Intact
Your roof is one of the most expensive parts of your home. Do not let a bad cleaning job void the warranty you paid for. Call Nick and Chris at 910-727-4336 for a free estimate on professional soft wash roof cleaning in Wilmington, Leland, Hampstead, or anywhere in Brunswick County. We protect your shingles, your landscaping, and your warranty on every job.
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