High moisture levels, humidity and overhanging trees cause moss growth on roofs. North-facing portions of roofs often accumulate moss from lack of sunlight and retaining moisture. Besides being aesthetically displeasing, moss can deteriorate roofing materials over time. Moss also impedes water drainage on roofs, which can cause leaks and other structural damages. Since the runoff from chemical solutions can harm vegetation, use natural solutions to kill roof moss. Biodegradable solutions attack moss without damaging roofing materials or the environment.
Trim thin tree branches that shade the roof, using gardening shears. Sweep the cut tree branches down and off the roof, using a telescoping pole brush.
Brush the moss down and off the roof, using the pole brush. Do not brush against the shingles, as they can break. Brush off as much moss as possible.
Mix liquid biodegradable moss removal soap with water in a garden sprayer tank. Read the manufacturer's directions on the product label for specific amounts of soap and water. Use a product that contains no bleach, acid or other chemicals.
Spray the solution directly onto the moss. Keep the solution on the roof for the amount of time recommended by the product manufacturer.
Brush the moss off the roof, using the pole brush. Rinse the roof with water from a garden hose, if recommended by the product manufacturer. Spray down the roof to prevent trapping water under the roofing materials.
Apply the solution in the morning or evening when the roof is cool to prevent the solution from evaporating too quickly. Install copper strips on the roof to prevent moss from returning.
Do not access the roof when it is wet or icy, as you could fall off. Wear proper safety gear while on the roof for preventive purposes.