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  • Eric Tremper

Keeping moss away: Moss removal and what to expect

Updated: Jan 30, 2019


Your roof has just been treated and you’re feeling accomplished that you took care of your roof. Over the next couple of weeks you start to wonder if it worked as you look up at moss still hanging around. It might even still look green and healthy!


Don't despair, moss treatments take time to work, but they are effective.




There are several products out there to kill the moss on the roof. Neighborhood Gutters is registered by the department of agriculture. Our go to treatment is powdered zinc. In the Pacific Northwest, moss is best treated while it is actively growing from fall to spring, during the rainy season. Powdered zinc works with the rain to dissolve into the roof. It will not only kill existing moss, but also prevent moss from growing.


Long-term results are not instant

Once the treatment is applied it can take weeks for the moss to show signs that it's dying. It will start turning an orangish color, then brown and should finally blacken from the summer sun. Some dead moss will come off with the weather, but most will shrivel up and linger around at the edge of the shingles. At this stage, the moss is no longer harming the roof. It's not acting like a sponge retaining water, and it's not pushing up on the shingle risking breaking the tar seal that holds the shingles down.


Left unchecked new moss will rapidly grow from the dead moss that has turned into an organic soil. It is recommended to treat the roof annually to prevent moss from growing, and it is especially important to not skip treatments if moss has established, until all of the dead remnants have eventually worn off of the roof.


The preventative benefits of regularly applying moss treatment to a roof can lead to big savings, not to mention the aesthetic perks.

What to do if moss has already taken hold

We often see roofs that have gone years without any roof maintenance. If the moss has become thick, the treatment alone will not be as effective.


The goal is to remove as much moss as possible while being gentle on the roof. We sweep off any moss that is thick and loose prior to the treatment. You should not expect all or even most of the moss to be removed. Any moss that cannot be gently removed needs to be treated.


Forcing off stuck-on moss will take roof along with it.

Top half of roof has been swept.

Even if sweeping were to remove most of the moss, it is still important to apply the treatment. Without it, all of the spores embedded in the roof will grow rapidly the next year.


Though sweeping is the most gentle way to remove the moss, it is better for the roof to just be covered in moss than to sweep it off year after year. Make annual treatments part of your fall or winter routine and your roof will thank you.




Neighborhood Gutters is registered by the department of agriculture.

Contact us for a quote on getting your roof treated for moss.


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