Protecting Your Roof from Moss

You may see moss on a roof and think that it looks rustic, or even cozy. Or you may think it’s simply an aesthetic annoyance. The truth about what moss can actually do to your roof is another story altogether. Here’s what you need to know about protecting your roof from moss.

Is Moss Really Bad for Your Roof?

The short answer is yes.

Mosses are very old plants and are non-vascular, meaning they don’t have root systems like vascular plants do. Instead, they have rhizoids that attach to all kinds of surfaces, such as roof shingles, even though there isn’t soil. The Pacific Northwest has the ideal climate for mosses to flourish. Mosses love damp and cool places to grow. The combination of long periods of light rain and large trees to provide shade makes Portland, and the rest of the Pacific Northwest, a breeding ground for moss.

Protecting Your Roof From Moss

There are a number of ways mosses can damage rooftops, but it really comes down to water. Because mosses don’t have roots to transport water to the plant body, they absorb water through diffusion directly into the plant body. This means that they act like sponges and can absorb and hold up to 20 times they’re weight. Holding moisture closely to shingles can cause them to deteriorate more quickly than they normally would. If moss were to get under a shingle, the shingle would be lifted which would allow water to leach underneath, rendering the shingle useless. A buildup of moss can create dams on your roof, increasing the likelihood of leaks.

One of the biggest threats to your roof is the changing of the seasons. Moss left on a roof through winter will amplify the freeze/ thaw effect, and can be quickly leave roofs vulnerable to weathering, deterioration, leaks and water damage. If left unchecked, it can cause serious harm to the structural integrity of the building.

While you probably don’t need to panic, it’s important to maintain your roof so you can avoid costly repairs in the future. Water damage repairs are not cheap! With each year left untreated, the damage to your roof can accelerate.

What to do if You Already Have a Moss Problem

The good news is that removing moss, especially if taken care of early, is something that can be easily and effectively done with the help of moss removal/ treatment professionals. There are thousands of different kinds of moss and many different kinds of rooftops. To avoid any damage to your property, it’s recommended to work with someone who has experience in working with different types of roofs to effectively remove the moss without damaging your shingles.

Roof Moss Removal

Whether your roof is metal, tile, slate, composition, or cedar shake, we can remove the moss. SNUGS has been removing moss from roofs for many years and has come across all different types of roofs. Some roofs need to be pressure washed, while other roofs will be destroyed from pressure washing. We can handle either situation and do the best to keep your roof in good condition. Once we clean the moss off the roof, we will clean the gutters and clean the moss from the ground. On composition roofs we will apply granular treatment to help prevent any spores from continuing to grow.

From pressure washing to using air compressors or brushing, making sure that the moss gets removed thoroughly while protecting your roof from damage is why calling the pros is highly recommended. Choosing the right method of removal and performing the removal process correctly can be tricky if you don’t have the proper experience.

Preventative Measures

Probably the most effective way to fight moss from taking over your roof is to use preventative measures. Because of the climate here in the Pacific Northwest, applying a preventative treatment annually is one of the best ways to keep moss off your roof. SNUGS is approved by the Department of Agriculture to apply treatments and remove moss. We use compounds that are registered with the EPA, and are proven to turn the moss inert. This treatment is applied in liquid form, and is recommended to be applied during the spring months, but can be applied year around.

Roof Moss Removal

Other preventative measures include:

  • Keeping your gutters clear so that there isn’t any backed up water that can encourage moss growth
  • keeping your roof clear of branches, leaves or other debris as they can hold moisture or prevent it from evaporating
  • Clearing any branches that create shade on the roof that would prevent evaporation

The goal is to keep your roof dry and clean so moss can’t gain a foothold. With the consecutive months of rain we experience here in the Pacific Northwest, prevention is crucial to maintaining your property.


Moss can do all kinds of damage to your roof and could potentially affect the structural integrity of the building itself. Removal and prevention of roof moss are vital to avoid costly repairs and to maintain your property so it will last for many years. SNUGS has been removing roof moss and treating roofs with moss control treatment for years. We have come across all different kinds of roofs and have the knowledge and experience to get remove and keep moss off your roof without damaging your property.

Snugs Pro Wash, Inc, dba SNUGS Services, has been providing high quality Pressure Washing Services in Portland, OR since 1995. Started as a residential pressure washing and roof cleaning service, SNUGS is now one of the leading exterior cleaning companies in the Northwest. From our humble beginnings as a man with a truck and a trailer we have grown to become a multi-million dollar company serving corporate customers, name brands, and mom and pop companies alike.

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