How to Get Rid of Lichen on the Roof

Set up the ladder on a flat, even surface. Tie a safety line to the ridge or chimney so you have some security while on the roof. Fill a spray bottle with a 50-50 mixture of water and household chlorine bleach. If you have an oxygenated bleach use that instead as it is gentler on any plants it might rain down upon.

Climb the ladder and spray the areas of lichen growth one at a time. The bleach will kill the organisms over the next several days and cause the adherence to loosen. Come back in three days to a week to see if they are dead and loose.

Scrub each lichen spot until it comes up from the roof shingles or tiles. Be careful not to scrub off the pebbles on asphalt shingles. You can also use a plastic spatula to chip the dead lichen off.

Rinse off the roof to remove the last vestiges of lichen. Apply zinc strips to the roof to reduce the growth of more lichens. The zinc slowly rinses down over the roof and prevents lichen, mold and algae.

Tack the zinc strips to the roof ridge. Affix more strips every 10 feet from the ridge line to the gutters. Slip the strips under the shingles and nail them to the roof every foot. You can also use copper strips.