October 2020

How To Remove Roof Moss the Eco-Friendly Way

A curved roof with a thick layer of moss growing on it. Moss covered roofs are a common problem in the Portland Metro Region.

It’s no secret that the Portland Metro Region gets A LOT of rain. On average, our region gets anywhere from 42-56 inches of rain per year. As a homeowner, this can pose a lot of challenges when it comes to gutters, foundations, roofs and more.

If you live in the Portland Metro Region and have a layer of moisture-loving moss growing on your roof, these tips are for you!

Moss can cause damage to your roof

Moss can grow in thick mats that capture and hold moisture. In the long term, this moisture can cause leaks and damage to your roof. Moss that grows on decks, sidewalks or driveways can also pose a slipping hazard.

Many moss-removal chemicals are harmful to humans and animals

Many off the shelf moss-removal chemicals can cause harm to you, your family and your pets. Hazardous chemicals include Ammonium sulfate, copper sulfate, ferric and ferrous sulfates, sodium pentachlorophenate, zinc chloride, and zinc sulfate. Keep your eyes peeled for these ingredients.

On rainy days, these chemicals may wash off your roof into your garden or pipes that feed into your local river. These chemicals can be toxic to our local animals and fish.

You have eco-friendly moss removal options

A yellow home in Portland, Oregon boasts a moss-free roof.

You have many eco-friendly options for removing moss from your roof.

Moss loves moist and shady conditions. You may reduce moss growth by pruning branches that shade your roof and removing nearby leaves, pine needles and branches. Once you carefully clear brush from your roof, you can use a garden hose or wet broom to push moss off of the roof. Pressure washers can also be used but are generally not recommended because they can damage roofing materials. Many local businesses can provide manual moss removal services.

There are also chemical removal options that are considered low in hazard. Potassium salts of fatty acids and ammonium salts of fatty acids are low-hazard active ingredients to look for. If you’re looking for a long term solution, installing metallic zinc strips on your roof can be a great solution. These metal strips stop or slow the growth of moss for years at a time.

Moss Removal Resources

Want to learn more about eco-friendly moss removal? Check out these resources:

Oregon Metro – Moss removal chemical hazards and removal recommendations

Grow Smart Grow Safe – Moss Control

Oregon State University – Moss on Roofs

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Our Annual Report is Live!

A canopy covers a informational booth for The River Starts Here in an open field. The booth is framed by a colorful sign and Salmon Toss Game, inviting community members to learn more about their watershed.

Each year, The River Starts Here publishes an annual report. The report lets us share our stories, successes, and lessons learned from the year with the community we serve – YOU!

The 2019-2020 Annual Report summarizes the Watershed Village, the first annual Student Video Contest, social media engagement, our budget and more. To learn more, download the Annual Report below.

Download the Annual Report

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