Roof Cleaning: How to Remove Moss and Algae from Your Roof

Moss and fungus are common growths seen on roofs. There is usually more fungus and moss on roofs in areas without humidity, simply because these growths favor moisture. Moss and fungus growth makes roofs look neglected and can decrease your home’s value and curb appeal. The moss and fungus growth appears as dark streaks on the roof and can spread fairly quickly. Moss and fungus don’t harm asphalt singled roofs, but because they are so unsightly, most homeowners remove such growth. Roof cleaning is a dangerous task and should be performed by roof cleaning professionals. DIY homeowners who have experience working on roofs in slippery conditions should use extreme caution when attempting to clean a roof. Although cleaning a roof successfully removes most moss and fungus, they usually return within a few months. Power Washing- Will It Damage Your Roof? Some homeowners use a power washer to clean their roofs. There is a debate  over whether power washing asphalt shingles can damage the shingles and cause leaks. If done with care, a power washing once a year will not damage an asphalt shingled roof. The problem is that many homeowners who decide to power wash do not do it properly, and they allow water to get under the shingles and leak into the home. Further, unless aimed in a downward direction, the force of the power washer can cause the shingles to break or loosen. If held downward and at least six inches away from the surface of the shingles, power washing should not damage your roof. However, power washing more than once a year can damage or shorten the life of asphalt shingles. How to Clean Your Roof Washing your roof with a roof cleaning product and garden hose is the best option for safely cleaning your roof. There are several products on the market specifically formulated to remove algae stains from roofs. Follow directions when using these products. Before cleaning your roof, contact the manufacturer of the shingles on your roof to see if it has any specific recommendations on cleaning. Homemade Roof Cleaner Make your own recipe for roof cleaning by mixing trisodium phosphate (TSP), bleach and water. Combine 1 quart bleach, ¼ cup TSP and 1 gallon water. Place in a spray bottle and spray onto the affected areas. Use a pump sprayer for larger roofs or roofs with lots of moss and fungus. Allow it to remain on the spots for about 15 minutes. Rinse off with a garden hose. Oxygen bleach can be used instead of the mixture mentioned above. It is known for lightening stains. Using oxygen bleach usually requires some scrubbing, but it works well for small areas with moss or fungus growth. Roof Cleaning Safety As with all roof-related projects, following proper safety precautions is essential. If possible, do not work alone, or at least make sure someone knows you’ll be up on the roof. •    Wear safety glasses or goggles. •    Wear work gloves. •    Wear non-slip shoes, such as rubber-soled shoes. •    Use a safety harness. •    Make sure your ladder is sturdy and secure.