Roofs with Asphalt Shingles and Fiberglass Panels
Scrub the surface using a mixture of one quart of chlorine bleach, 1 ounce detergent, and 1 gallon water at the rate of 1 gallon per about 40 square feet.
Wood Shingles
Scrub surfaces with a solution of 1 quart chlorine bleach and 1 ounce detergent in 1 gallon water. Rinse thoroughly. If stains remain, increase the concentration of bleach to water and re-treat. Allow wood to dry thoroughly before painting or enclosing.
This solution will damage metal rain gutters and plants, so control runoff and rinse surfaces contacted by the solution.
Correct the damp conditions that led to the mold growth or mold will return. Trim trees and remove other things that limit airflow to the roof.
