Roof Cleaning FAQs: What You Need to Know Before Hiring A PROFESSIONAL

The good news is YES! P3 offers a no-pressure roof cleaning service that safely kills and removes algae—no pressure washer needed. This method restores both the appearance of your roof and the integrity of your shingles.

The safest way is by using the no-pressure chemical cleaning methods recommended by the Asphalt Roofing Manufacturers Association, GAF, and Owens Corning. These methods effectively remove algae without harming your shingles. Damage often occurs when inexperienced contractors—or homeowners—use high-pressure washing, which strips away the protective granules (also known as aggregate or gravel) on the shingles. Never allow a pressure washer or any aggressive cleaning method to be used on your roof.

The recommended cleaning solution—according to ARMA (Asphalt Roofing Manufacturers Association), GAF, and Owens Corning—is a bleach-based mix combined with safe pH cleaners. This solution effectively kills roof algae and helps keep your roof clean for up to 5 years. At P3, we apply it using our proprietary low-pressure pump system, which uses even less pressure than a standard garden hose. In contrast, most pressure washers start at 500 PSI or more—far too much pressure for roofing shingles to safely handle.

Unfortunately, no. Shingle manufacturers do not recommend these products because they’re generally ineffective on their own. They often require high-pressure washing to see results—which can damage your shingles and shorten the life of your roof. Without pressure, some of these cleaners even state on the label that it may take 2–3 months to see any visible improvement, and multiple applications may be needed.

It can—if not handled properly. After all, roof algae are a form of plant life, and the solution is designed to kill them. That’s why it’s important to hire a professional. At P3, we take every precaution to protect your landscaping, your family, and your home. Our team is trained to apply the solution safely and effectively, minimizing any risk to your property.

Some biocides and sealers claim to prevent algae growth long-term, but test results are limited, so their effectiveness isn't guaranteed. The most reliable approach is annual maintenance. For less than $100 a year, we’ll apply a maintenance coat to help prevent algae from coming back—keeping your roof looking clean and lasting longer.

They’re called algae-resistant—not algae-proof—for a reason. These shingles do help reduce algae growth, but they’re not a guaranteed, long-term solution. In my experience as a roof cleaning contractor, I’ve seen algae-resistant shingles start showing signs of algae after about 10 years. At that point, a no-pressure roof cleaning is still the safest and most effective option.

Ideally, you should have your roof cleaned at the first sign of black streaks or fungus growth. Unfortunately, many homeowners assume it will go away on its own and wait until the roof is heavily stained—by then, cleaning is often more expensive. In warmer regions like Florida, Georgia, and the Carolinas, roof cleaning can be done year-round due to the mild climate.

Pricing depends on the size and pitch of your roof, but generally, cleaning costs hundreds—not thousands like a full roof replacement. Plus, a proper cleaning can last 3 to 5 years. It’s a smart investment!

Roof cleaning is still a relatively new service in North Carolina, and for some companies, it’s just a sideline. Be sure to ask for references and proof of insurance. P3 is fully insured, a licensed LLC, and happy to provide all necessary documentation upon request.