How to Remove Moss from Your Roof (and Stop It from Growing Back)

Is your roof going way too green? Use these materials, tools, and methods to eradicate moss from your rooftop—and keep it from coming back.

Overhead greenery should be limited to the leaves on tree canopies. If moss is covering your roof, it's time to get cleaning. Moss grows in areas untouched by sun, so it can develop at a speedy pace on tree-shaded and north-facing roofs. Spreading moss can quickly adhere to roof surfaces, filling in voids between shingles and tiles, and reaching under and lifting up roofing materials. This heaving of shingles allows rainwater and other moisture to seep into your roof's structure to cause decay and rot.

fall foliage and gray home exterior with stone pillars
Anthony Masterson

Before you clean the moss off your roof, you'll need to consider how you want to kill the plants and remove the dead layers. After cleaning, you'll also need to put some defensive measures into play to prevent the moss from growing back.

Experts recommend that you save roof-moss removal for a cloudy day. This is because roof-cleaning products, which should be left to absorb into the moss for at least 20 minutes, will not evaporate as quickly as they might on sunny days. Moss can be removed physically with water and a stiff brush on a pole, or with a scrub brush, chemically, or by using a bit of both. Opt for the least-toxic solution. Chemical solutions can adversely affect the environment, as well as cause damage to plants growing beneath the overhangs. If you decide to use a bleach solution, or a readymade roof-moss treatment, protect nearby plants with plastic sheeting. You might also want to hose down the plants, shrubs, and small trees with water once you've finished. The coating of water will dilute chemicals that may have spilled down from the eaves. Here are a few moss-removal solutions for your roof that you can buy or create yourself.

Moss-Removal Products and DIY Solutions

Some readymade cleaners, like Wet and Forget Liquid Mold Remover ($30, Walmart), can be mixed and applied per manufacturer's instructions and left to kill the moss with no rinsing required. Others, like Bio-Advanced Moss and Algae Killer ($19, The Home Depot), are available in ready-to-go sprays that hook up to your hose. To ensure your safety, and protect your roof tiles, shingles, and plantings, follow the mixing and application recommendations.

You can also make your own moss remover. These are generally less toxic than their chemical counterparts. Chlorine bleach removes mosses, fungi, and mildew, but it may damage plants, so dilute it before you spray it on your roof. A good formula is to mix one quart bleach with one gallon of water and 1/4 cup heavy-duty cleaner, like trisodium phosphate. Don't use ammonia-based cleaners, since they create toxic fumes when mixed with bleach.

Or, make a plant-friendlier solution of 1 cup oxygen bleach and 1 gallon of water. Home improvement expert Bob Vila says you can also mix 8 ounces of Dawn dish liquid or 1-1/2 to 3-1/2 cups of white distilled vinegar with 2 gallons of water. Pour solutions into a pump garden-style sprayer; choose a backpack-type sprayer ($90, Ace Hardware), which will be safer to use if you're climbing and standing on a ladder.

Once you've decided on your solution, it's time to get started. Follow these step-by-step instructions to rid your roof of moss and any other debris that's accumulated.

moss on house roof
Lex20/Getty Images

How to Remove Moss from Roof Tiles

Learn how to remove moss from rooftops with our easy instructions.

What You'll Need:

  • Safety glasses or goggles
  • Rubber gloves
  • Safety rope
  • Work clothes, a cap to protect your hair, and slip-resistant footwear
  • Ladder
  • Garden hose equipped with a spray nozzle
  • Moss-remover of choice
  • Backpack-style garden pump sprayer or a large spray bottle
  • Scrub brush
  • Long-handled soft-bristle brush
  • Power washer (optional)

Step 1: Prep Space

No matter which method you choose, you're going to get dirty, so dress appropriately—wear old clothes, safety glasses, rubber gloves, a cap, and slip-resistant shoes. Have a safety rope or harness handy if you're headed to the peak of your roof. Cover nearby plants with plastic sheeting. Set a ladder securely in place, grab the hose, and start climbing.

Step 2: Spray the Roof with Water

Spray all the moss-covered sections with water. Always work from the top of the roof downward to ensure the water pours off, and neither it nor the tools lift or break the shingles and tiles.

Step 3: Scrub the Shingles

Before applying a moss-removing cleaner, use a scrub brush ($3-$15, The Home Depot), or a long-handled soft-bristle brush, to gently scrape or pluck moss from the shingles or tiles. Work on one small section at a time, which allows you better control of the brush and your scrubbing motions. Move the brush downward to protect the shingles from breakage.

Step 4: Apply Moss Remover

If you still need a chemical solution, use a pump sprayer ($37, Walmart), or large spray bottle to apply your preferred remover. Soak the moss and let the solution set according to the manufacturer's instructions. If you're using a homemade remover, let it set for about 20 minutes.

Step 5: Rinse the Roof

Grab the hose, climb up the ladder, and rinse off the solution and now-dead moss. Remove any remaining moss with a scrub brush, and rinse the roof again.

Step 6: Power-Wash Roof (Optional)

Alternatively, you can use a power washer to clean away moss, but there are several caveats to consider. First, you need to ensure that roof shingles and tiles are not broken, chipped, or damaged, as water applied at high pressure is likely to amplify the damage and seep through any cracks. Also, when you're using a power washer, you'll need to stand on the roof, above the mold, so you can point the power washer in a downward direction. If you opt for this method, use it on the lowest pressure setting possible.

gray home exterior with shakers and arched front entry
Stacey Branford

How to Prevent Moss on Your Roof

Happily, there are preventive measures you can use to keep your roof moss-free. First, let the sunshine in. Trim any branches hanging over your roof, keep the gutters free of debris, and regularly remove moisture-collectors—such as leaves, branches, and seedpods—that pile up on the roof and encourage moss to grow. The best long-term solution is to attach strips of zinc ($41, The Home Depot) or zinc-coated metal flashing strips just below the peak or ridge caps. When it rains, water flows over the metal strips leaching out moss-retardant zinc particles, which attach to roof shingles and/or tiles to stop new moss from forming.

Working safely, smartly, and strategically guarantees your operations will run smoothly. These prevention measures mean you'll be able to stay off the ladder and roof for seasons, if not years, to come.

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