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.
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.
