Things You'll Need
Chlorine bleach or oxygen bleach
1 cup powdered laundry soap
Pump garden sprayer
Roof shingles can become dirty and stained over time. Algae, mold, mildew, moss and dirt are often attracted to shingles. Bleach can effectively clean roof shingles and remove even the toughest stains. Keeping roof shingles clean will not only enhance the overall look of your home, but can also protect the shingles from damage caused by moss and mildew.
Mix 1 gallon hot water, 1 cup chlorine bleach and 1 cup powdered laundry soap into a large bucket. Use an extra-long paint stirrer or similar item to thoroughly mix the contents together.
Fill the reservoir on a garden sprayer with the cleaning solution. Pour the contents directly from the bucket into the garden sprayer until the sprayer reservoir is full.
Apply a generous coating of the cleaning solution to the roof using the garden sprayer. Work from the bottom to the top when cleaning the shingles so that you can avoid standing on wet areas of the shingled roof. Saturate a 3-foot high by 10-foot wide section of the roof and allow the solution to sit on the shingles for about 15 minutes.
Scrub the wet area of the shingled roof with a stiff-bristled broom. Apply some force to thoroughly remove any mold, algae or other stains. It is important to keep each section of the roof wet while working on that specific area. If the shingles begin to dry, apply more cleaning solution as you scrub.
Rinse the cleaning solution from that section of the roof with plain water from a garden hose. Rinse from the top of the section to the bottom to avoid restaining the shingles with dirty water.
Repeat this process, working in small sections at one time, until the entire shingled surface is clean.
Use oxygen bleach as an alternative method for cleaning shingles. Mix a solution of oxygen bleach and water into a garden sprayer. The ratio of oxygen bleach to water will depend on the concentration of sodium percarbonate in the product you are using. Refer to the mixing instructions on the label for specific instructions. Apply the oxygen bleach to the shingles just as you would the chlorine bleach, then rinse with plain water from the garden hose.
Clean roof shingles on a cool, overcast day to prevent the cleaning solution from drying on the roof too quickly.
Wear rubber-soled shoes with good gripping when cleaning the roof to reduce the chance of slipping.