Zinc strips are generally considered the best option for long-term suppression of moss on roofs. Zinc strips or galvanised flashing release metallic zinc with each rainfall, killing mosses below the strip. This relatively safe and inexpensive material kills or retards the growth of moss and fungi up to 15 feet below the strip. Most brands of zinc strips are considered to be effective for up to one year, and the impact of galvanised flashing can persist for decades. Success of moss control depends on local climate and the rate of moss development.
For the best results, use the scraper to remove existing moss before installing zinc strips or flashing.
Apply the rolled zinc or galvanised flashing to each side of ridge caps along roof peaks.
Pound a nail every foot along the strip.
Ensure that zinc-laden runoff from the roof does not directly flow to surrounding vegetation, fish ponds or water supplies, as some contamination is likely to occur.
Always use caution and proper safety procedures when working on a roof.