Remove Moss From Your Roof with These Expert Tips

If you’re a homeowner in cities like Portland, Seattle, Vancouver, or even on the East Coast in places like Boston or New York, where damp climates are common, dealing with moss growth is a persistent and costly issue. Sure, moss-covered roofs may look charming, but moss retains moisture, weakens roofing materials, and can lead to expensive repairs if left untreated. 

To help you protect the health and longevity of your roof—whether it’s a cozy cottage, modern townhouse or a single-family home—we interviewed industry experts who shared their insights in this Redfin article on nature’s green rug, the best ways to remove moss from your roof, and how to prevent it from returning.

Why moss grows on roofs in the first place

If your roof gets little sunlight—especially if it’s under trees or facing north—you’re more likely to see moss buildup over time. Patrick Roden of On Top Home Services explains, “Moss thrives in cool, damp areas with limited sunlight, like shaded roofs where moisture is retained.” 

Moss spreads through windblown spores, meaning even if you clean your roof, new spores can still settle. Roden also notes that leaves and branches trap moisture, further fueling moss growth. Certain roofing materials, like asphalt shingles filled with calcium carbonate, are particularly vulnerable to moss. “Moss can cling to shingles and other materials and retain water, which can lead to the growth of fungi and accelerate roof decay,” he warns.

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Is moss really that bad for your roof?

Moss may seem harmless, but it can cause serious damage to your roof. Chris Sloan of Sloan’s Home Solutions explains, “Moss retains moisture and can cause roofing materials to deteriorate faster. Over time, it can lead to leaks, rot, and structural damage.” Once moss begins to grow, it can “lift shingles and tiles, which allows water to seep underneath. This can compromise the roof’s waterproof barrier and shorten its lifespan.”

Sloan also stresses the importance of safety during moss removal: “Always prioritize safety: use fall protection gear, work with a buddy, and avoid walking on the roof when it’s wet or slippery.”

Common methods for removing moss from your roof

Moss removal is essential for maintaining both the aesthetics and integrity of your roof. Joseph Mollo of Atlantic Pressure Washing advises using a soft-bristle brush for manual removal: “A soft-bristle brush is ideal for gently loosening moss from the surface without damaging shingles.” He warns against aggressive scrubbing, which can strip shingles of their protective granules, and stresses that pressure washing should be avoided. “Pressure washing can strip away shingle granules and reduce your roof’s lifespan,” Mollo says. For natural treatments, Mollo recommends “there are biodegradable moss prevention sprays available. These treatments contain ingredients like potassium salts or citrus-based solutions that stop moss from growing without harming the environment. They need to be reapplied periodically, especially after heavy rainfall.”

Moss removal isn’t just about looks; it’s crucial for maintaining your roof’s health. Sandy Prisak of Roof Shampoo® emphasizes the importance of roof cleanliness for curb appeal: “If a listing has a dirty roof, it will be one of the very first things a buyer sees.” Moss buildup can hurt your home’s marketability, so addressing it promptly is essential.

Aaron of Roof Moss Gone highlights the significance of following industry guidelines when cleaning roofs: “The Asphalt Roofing Manufacturers Association (ARMA) states on their website that composition roofs should be cleaned with a mixture of 50% water and 50% sodium hypochlorite.” While DIY moss removal is an option, Aaron advises that homeowners only take it on if they’re professionally trained to ensure safety and effectiveness.

How much does it cost to remove moss from a roof?

The cost of moss removal varies based on your home’s size and the extent of moss buildup. Alex Sirotinskiy of Surface Renewal estimates that professional moss removal can cost between $350 and $1,200, including the application of a liquid moss treatment. “Homes with extensive moss buildup or larger roof surfaces will naturally fall on the higher end of the price range,” he notes.

Regular roof inspections and cleanings are key to preventing moss from returning. “At least every 15 months to two years is a minimum,” Sirotinskiy advises. Routine maintenance can save money in the long run by reducing the risk of expensive repairs or full roof replacement.

Avoid these common mistakes when removing moss from your roof

Adam Newton of Olympia Moss Removal cautions against using pressure washers, which can damage shingles and void warranties: “Pressure washing can easily take the shingle topper off with the moss.” He also warns DIYers to be careful when climbing on the roof: “The overly ambitious (but well intended) homeowner puts themselves in a precarious situation by climbing on the roof.”

Newton advises using a soft wash method, which involves low-pressure cleaning solutions that effectively remove moss without damaging shingles. If damage occurs, such as torn shingle edges or exposed nails, Newton suggests using rubberized sealant for minor repairs. For more extensive damage, he recommends contacting a roofing contractor.

What happens if moss removal is delayed?

Neglecting moss can have long-term consequences. Newton explains, “Moss acts like a sponge and traps moisture in place, which can wear down the shingle topper and affect the lifespan of the roof.” For severe cases, a professional soft wash service may be necessary to restore your roof.

Taking proactive steps to prevent moss growth and addressing it promptly will help extend your roof’s lifespan, maintain your home’s value, and avoid a costly roof replacement  down the line.