How To: Remove Moss from the Roof
A layer of green moss might look rustic atop your house, but it can drastically shorten your roof’s lifespan. Follow these three straightforward steps to clean off moss—and keep it from coming back
STEP 1 Carefully place a ladder near the area of moss growth, and don slip-resistant shoes, old clothes, rubber gloves, and eye protection. (You may also want to secure yourself with a safety rope.) Hose off the area with plain water, spraying at a downward angle. Then, use a long-handled soft-bristle scrub brush to remove the moss from the roof, scrubbing from the top down to avoid lifting shingles. As you continue, rub gently—don’t scrape, scour, or pound on the roof—and work in one small section at a time to avoid ripping, cracking, or breaking the shingles. Note: Don’t use a pressure washer on the roof. The high-powered water jets can damage shingles and remove the shingle granules that protect the roof.
Some popular cleansers include Wet & Forget, a spray-on product for removing moss, mold, and mildew; Bayer 2-in-1 Moss and Algae Killer, a potassium soap of fatty acids and inert ingredients that you mix with water and then spray on; and Moss B Ware, a 99 percent zinc sulfate monohydrate powder that can be applied dry or mixed with water. Whichever you choose, follow the manufacturer’s directions for application; some cleansers should be rinsed off after use, while others specify to be left on. You also can make your own moss remover in a large spray bottle with one of these four DIY recipes: • 8 ounces Dawn Ultra dish soap + 2 gallons of water • 1 pound powdered oxygen bleach + 2 gallons of water • 1½ to 3½ cups chlorine bleach + 2 gallons of water • 1½ to 3½ cups white distilled vinegar + 2 gallons of water For any of these homemade options, you’ll want to wet down the roof with plain water first, then apply the cleanser and let it sit for 20 to 45 minutes. Lightly scrub with a soft-bristle brush, then rinse with water.