How to remove moss on a roofRegular maintenance is the best way to help extend the life of the various components within a home and to keep them operating properly. One of the most important areas of a home is the roof, which serves to protect the interior from rain, hail, debris, and wind. Regularly cleaning and performing preventative maintenance is critical in order to prevent leakage or damage. However, improperly cleaning your roof can not only leave it functioning less than ideally, some practices can actually lead to damage or shortening its lifespan. Below, we will go through several ways to properly clean an asphalt shingle roof and some ways to avoid.

Similar to a gutter and downspout system, roofs should be regularly cleaned and maintained (typically twice a year). This not only helps to prolong the life of the roof materials, but also helps to identify potential problem areas to repair before they lead to damage. Sealing fasteners, removing debris (leaf litter, branches, pine cones, etc), and ensuring that flashing remains in place around penetrations are some common areas to check and maintain on a regular basis.

Clean moss off of a roofAnother common item for asphalt shingle roofs that needs regular attention in the Pacific Northwest is the removal and/or treatment of moss, lichen, and algae build up. Most commonly found on the north and west sides of a roof (or any areas with consistent shade), moss buildup can hold moisture against the shingles. Since shingles are designed to shed water, this can lead to deterioration of the shingle and potential leakage. Other common growths include unsightly black streaks of blue-green algae and white or yellow growths of lichen.

While many homeowners use pressure washers to clean asphalt shingle roofs, this can severely damage the shingles and take years off its lifespan. Instead, use a sprayer attached to a garden hose to spray a chlorine bleach solution or moss remover over the shingles to kill the moss growth. After moss has been killed by the moss remover, it will loosen from the shingles and can be blown off with a leaf blower or lightly brushed off with a push broom. Applying the solution on a dry overcast day is best in order to prevent the solution from drying out too quickly in the sun or being diluted with rain.

Keep in mind the discharge location of the solution or remover as the chemicals can kill plants in your landscaping and redirecting the downspout extensions away from plants is important. Always use a hose bib that is protected with a backflow preventer or vacuum breaker to avoid water contaminated with chemicals back siphoning into the water distribution system. Lastly, always be safe when working on or around your roof as it can be slippery and dangerous.