A mixture of Clorox chlorine bleach, trisodium phosphate and water can be used to clean asphalt shingles. The trisodium phosphate allows the bleach to work more efficiently, but if it's not available, a non-ammonia based laundry detergent or heavy duty cleanser can also be used. Depending on the size of the home, cleaning the roof can typically take a single afternoon to complete.
Before you startConnect a garden hose to fresh water, set the ladder in place and make sure you have proper safety equipment, such as goggles and protective gloves. You will also need a handheld sprayer or container to apply the solution to the shingles. Additionally, be sure to choose a sunny day to clean the shingles to ensure the bleach solution works properly.
Mix the cleaning solution
Make a cleaning solution that contains a quart of Clorox chlorine bleach, 1/4 cup of trisodium phosphate and a gallon of water. Trisodium phosphate can be replaced with 1/2 cup of laundry detergent.
Spray the roof with the cleaning solution
Pour the mixture into a handheld sprayer, then spray the shingles thoroughly. If a handheld sprayer isn't available, use a bucket or another container to pour the solution onto the roof. Allow the solution to remain on the shingles for 15 to 30 minutes.
Rinse the roof, house and nearby plants
Use a garden hose to rinse the roof, the home's siding and plants that lie nearby.