Cushiony green growth on roofs indicates moss, which is a rapid-growing, flowerless plant. Roofs with poor drainage are likely to harbour moss, since moss flourishes in moist environments. Abundant shade and vegetation are also responsible for moss growth on shingles. Moss, no matter how cottage-like it appears, is actually harmful to roofs. Failure to control moss on roofs allows it to eventually penetrate and destroy shingles. Moss build-up also inhibits essential water drainage on roofs, which leads to leaks. Remove moss from your roof as soon as possible using basic supplies.
Dampen any vegetation around your home's foundation with water to prevent bleach from damaging any vegetation. Cover the ground below the roof line with heavy-duty dust sheets to further protect exposed vegetation.
Protect yourself from the bleach solution, as well. Put on rubber gloves, non-slip shoes (for roof safety), and safety glasses.
Mix together 1 qt. of water and 1 qt. of ordinary chlorine bleach in a pail. Pour the bleach solution into the garden sprayer.
Spray the bleach solution evenly and liberally over the mossy roof. Let the moss absorb the diluted bleach for 30 minutes.
Rinse the dead moss growth off the roof's surface using the garden hose. Blast water down the roof's slope, not against the slope.
Trim back excess vegetation to eliminate moss growth on your roof.
Icy roofs are too dangerous to access. Work cautiously on the rooftop at all times, especially if the roof's slope is steep.