Why is moss on a roof such a big deal? Moss damages roofs by retaining moisture, so a roof never completely dries out. This leads to warped shingles and rotten sheeting. Here are tips on how to get rid of roof moss from the experts at This Old House.
Don’t just go up on a roof and start cleaning. Gather together a ladder, safety harnesses, lines, and brackets specifically made for roofing safety. Get a roofing brush. Never use a power washer, since the water may do more damage to your roof than the moss.
Sweep the Roof
Using the roof brush, gently sweep the roof. Just worry about removing the biggest pieces for now.
Metal Strip Application
Install a metal strip along the rooftop. The strip, often made of zinc, lead, or copper, looks like a big roll of duct tape. When rain falls on the metal strip, it will pour tiny bits of the metal all over the roof, killing the remaining moss, lichen, and mold. The strips need to be hammered into place. Seal the nail hole with roofing caulk.
Inside of a pump spray, mix a third of a gallon of bleach and one and a half gallons of water. This kills the remaining moss. If any plants are around the house, they may die from the bleach. To prevent this, spray them with pure water as soon as possible to remove the bleach.