Why Moss Grows on Washington Roofs and How To Stop It
It’s probably safe to say that most people don’t like pulling into the driveway after a long day of work to the sight of a patchy green roof, but unfortunately, this is the common reality for many who live in Washington. Thanks to the cool, damp climate here in our home state, moss is a persistent issue that can cause severe damage to your roof that may even lead to the need for a full-roof replacement. In this guide, we’ll give you a rundown on why moss might make a foothold on your roof, how to get rid of it, and how to make sure it never does again.
Moss Growth in Washington State
Climate Contributors
Western Washington’s climate creates the perfect breeding ground for moss. The area’s frequent rain, high humidity, and overcast skies make it the perfect habitat for plant growth. Unlike other plants, moss doesn’t need soil to grow—it simply absorbs moisture from the air, making rooftops a great place for colonization.
Personal Environment Contributors
Along with general parts of the climate in Washington, there are several more individual factors that can contribute to moss growth on your property. Overhanging trees leave shade and debris that keep your roof moist for extended periods of time, and sometimes the type of roofing material you choose can affect how your roof fosters moss growth. For instance, asphalt roofs are much more susceptible to moisture than metal roofs. It’s good to keep these factors in mind when thinking about how and where to install your roof, or wondering why the moss sticks.
The Impact of Moss on Roofs
Structural Concerns
Moss retains moisture, which can not only speed up the wear and tear timeline of your roof, but even lead to rot if left untreated for a long period of time. Excessive moss growth can also lift shingles out of place, letting water seep underneath and causing leaks.
Lowering Property Value
Along with causing physical damage to your home, (unless you’re purposefully going for a green roof look) moss is simply not very nice to look at. It doesn’t belong on your roof, and lessens property value and curb appeal.
Preventing Moss Growth
Regular Roof Maintenance
- Inspect your roof at least twice a year for signs of moss.
- Remove leaves, twigs, and other debris that may trap moisture.
- Schedule professional roof cleaning services to prevent buildup.
Managing Trees and Vegetation
- Trim overhanging branches to allow more sunlight to reach the roof.
- Keep vegetation at least a few feet away from the home to improve air circulation.
Gutter Cleaning
- Ensure gutters are free from blockages to prevent water from pooling on the roof.
- Regularly check downspouts for proper drainage.
Removing the Moss
Natural Remedies
There are several good ways to get rid of moss, but if you want to go the natural route, you’ll want to stick with baking soda or vinegar. Sprinkling the moss with baking soda dries it out and prevents further growth; the moss is easily scraped off after a few days of this treatment. Spraying the moss with white vinegar has similar effects, though it should be washed off with water, not just scraped away.
Chemical Treatments
If using natural remedies sounds like too much work, zinc sulfate and potassium salts of fatty acids are both great alternate choices. Zinc sulfate is a very effective weed killer, while potassium salts of fatty acids are a slightly more environmentally sound option that’s safe around children and pets.
Keeping It Gone
To keep that moss away once you’ve gotten rid of it, you might consider installing copper or zinc strips that release ions that prevent moss growth along the roof’s ridge. If you have shingles that are persistently covered in moss, we recommend replacing your current roof with algae and moss resistant shingles that are infused with copper or zinc to prevent plant growth.
When To Call a Professional
If large patches of thick, persistent moss won’t go away with DIY treatments, your roof is damaged, or there are leaks and moisture damage inside your home, it’s time to contact a professional. Professional roofers have all the expertise and experience necessary to ensure a job well-done.
Why Trust the Roof Doctor with Your Mossy Roof?
With over 60 years of experience serving western Washington, The Roof Doctor is committed to keeping your roof in top condition. As a family-owned and operated business, we take pride in delivering reliable, high-quality service with a focus on customer satisfaction. Whether you need routine maintenance or a complete roof overhaul, our skilled team is here to ensure your home stays safe and protected from the elements.