Moss Removal and Treatment in Seattle

Every year, like clock-work, PNW homeowners can count on seeing moss appear on their roofs, sidewalks and any sort of porous material that is out of reach of the sun. Heavy rain flow and lack of sunshine throughout the seasons contribute to the growth of moss which can eventually lead to the decay and deterioration of your home’s exterior; the most concerning of which is your roof. Our moss removal and treatment service allows your roof and other features to remain intact, healthy, and will prevent moss growth during the rainy season.

Why Moss Suppression?

Seattle Washington, also known as the evergreen state, is home to an impressive number of vegetation, including moss. Shady north facing areas on your property are more likely to see the growth of moss, the most concerning area being your roof. Moss, similar to a sponge, retains moisture in its green mass and, over time, can jeopardize the longevity of your roof and contribute to erosion. We recommend taking preventative measures to deter the undeniable growth of moss and maintain the integrity of your roof and structure.

Damp areas between your roof and ceiling could also easily become colonies for lichen, mold, and other fungi. Removing moss accumulation early and treating your roof regularly prevents such growth and deterioration before the damage becomes too difficult and costly to manage.

moss removal seattle
roof moss cleaning

Why Moss Removal?

Similar to a sponge, moss retains moisture and over time it can jeopardize the longevity of your roof. Damp areas between your roof and ceiling could also easily become colonies for lichen, mold, and other fungi. Removing unsightly moss accumulation and treating your roof regularly prevents such growth and deterioration before a costly repair is needed. 

We’ll help you take preventative measures to deter the growth of moss and maintain the integrity of your home’s roof!

Job Satisfaction Guaranteed

Renova is committed to its work and customer service as part of our effort to maintain long-term partnerships within our community. We make any return trips needed, at no cost to you, until you’ve expressed your full satisfaction with the moss removal on your roof.


We do all moss removal by hand. Using brushes, we loosen the moss from the edges of the shingles and then clear the loose debris from the roof with a leaf blower. The physical removal of moss by hand is the most labor-intensive part of our service, but we prefer this method to all others because it is extremely effective in removing moss while still

being gentle on the roof.

While no treatment can permanently stop moss from returning, our post-removal treatment will significantly slow down regrowth, keeping your roof cleaner for much longer. Due to our very damp climate in the Pacific NW, we highly recommend having some preventative treatment applied to your roof every year in conjunction with regular gutter maintenance. This will extend the life of your roof and ensure that moss does not have an opportunity to take root and grow back.

Yes, but if you have substantial moss growth on your roof, we strongly advise against this.

While the treatment may kill most or all of the moss on the roof, it will not make the moss ‘go away’ or magically vanish. Once treated, the moss will start to dry up and turn brown. Dead moss tends to stay stuck to the roof and can be unsightly and continue to cause water dams and other issues.

Eventually, depending on the pitch of your roof, some of the larger pieces may begin to break off and roll down into the gutters or fall on the ground while the smaller bits of moss will still be visible and stuck to the roof. Treatment without removal can help keep moss growth in check, but in our experience, it is far better to have the moss removed first. There are, however, rare instances in which the shingles are so old and fragile that treatment without removal is the only viable option.

NO! Please do not ever let a service provider pressure wash your roof! This will immediately void your warranty and can cause permanent damage to your roof. There is also a risk of water penetration and leaks.

Our moss treatment is a safe and effective way to prevent and slow moss growth on roofs. The treatment is a white granular powder that is applied to the roof and dissolves in moisture. As the treatment works its way down through the shingles, it kills the moss spores and changes the PH of the roof so moss is unable to grow.

Yes, our treatment is safe, environmentally friendly, and is also zinc-free. Many other moss

treatment products on the market use zinc as the active ingredient, which is hard on our salmon and marine life. For more details, please contact us and we will provide you with a detailed environmental material safety data sheet (MSDS) with the specifics.

As long as we have access to the exterior of your home, we can perform the moss removal without you needing to be home. We'll ensure everything is left tidy and secure.

Please have all windows closed until the service is complete to ensure no dust or particulate from the roof finds its way into your home. We appreciate it if you could clear any vehicles or furniture away from the immediate work area. If you have pets, keeping them inside during our visit helps ensure their safety and ours.

Unless discussed in advance, we will utilize your yard waste bin to dispose of moss, leaves, and other natural detritus from the roof and gutters. If there is not adequate room in your yard waste bin, we will leave a compostable garden bag by your bins for pick-up by the city.

If there is fencing very near your home, or if there are narrow walkways alongside the house, we may need access to a neighbor’s yard to safely position ladders to get up to your roofline. Most of the time this is something we see in advance and will communicate to you in conjunction with your quote, but there are instances in which we run into an ‘ease-of-access’ issue onsite and have to make last minute adjustments. If this occurs, we will make every effort to be just as respectful and courteous to your neighbors and their property as we are to you and yours.

Moss treatment will be visible on the roof for a few weeks. This is completely normal and will not damage or discolor the roof. However, the visible traces of treatment may be of concern if we are helping you prep your home for sale because they will be visible in photos if applied too close to the date of your photography session. If this is a concern please let us know and we can provide an alternative liquid treatment that will dry clear and not be visible in photos.

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