How to Get Rid of Moss on Your Roof — Seattle Homeowner’s Guide

The Seattle Moss Problem

Moss on roofs is a common sight in the Greater Seattle area. As a local roof cleaning contractor with experience serving over 10,000 customers, we understand the challenges this organic growth presents. This guide focuses specifically on moss removal from asphalt shingled roofs (the most common in the Seattle area), not from concrete, trees, or lawns. Getting rid of moss and maintaining a moss-free roof will enhance your home’s curb appeal and potentially save you money on costly repairs in the long run.

Proactive Moss Control: The Key to a Healthy Seattle Roof

The best way to handle moss is to prevent it from becoming a problem in the first place. Regular roof maintenance is key, especially given Seattle’s damp climate.

Regular Maintenance: How to Prevent Moss on Your Roof in Seattle

Moss thrives in moist environments like Seattle. To keep your roof dry, regularly remove debris such as leaves, pine needles, and other loose materials. These materials trap moisture, creating an ideal environment for moss growth. Consider trimming or removing trees or vegetation that heavily shade your roof to reduce moisture retention.

DIY Moss Treatments for Seattle Roofs

When clearing debris, apply a moss treatment. Zinc sulfate is readily available at most hardware stores. Other pre-mixed treatments can be attached to a garden hose for easy application.

• Bleach Solution: Many roof manufacturers recommend using a bleach and water solution. Mix one gallon of bleach with one gallon of water and apply it with a pump sprayer.

Disclaimer: Always exercise caution and protect yourself and the surrounding area when applying any treatment.

These treatments are most effective for light moss growth.

Heavy Moss Build-Up: What Not to Do When Removing Moss in Seattle

Many homeowners and even some contractors make the mistake of pressure washing, brushing, or scraping moss from asphalt shingles. This can severely damage your roof.

Why Pressure Washing is Bad for Seattle Roofs

Pressure washers, typically outputting around 3000 PSI, are too powerful for asphalt shingles. High pressure can remove the protective granules from the shingles and even lift and damage the shingles themselves.

The Problem with Brushing or Scraping Moss

Moss roots itself into asphalt shingles. Brushing or scraping removes the granules along with the moss, shortening the lifespan of your roof.

The Best Approach: Killing Moss on Asphalt Shingles in the Seattle Area

For heavy moss, the best approach is to kill the moss and allow it to naturally deteriorate. Bleach (soft washing) is effective for this, and is best to have a professional apply. While it requires patience, it’s far less damaging than aggressive removal methods.

Given that most roofs in Seattle have an expected lifespan of 30-50 years, a single aggressive cleaning can significantly reduce that lifespan.

A Gentle Approach to Moss Removal in Seattle

We recommend applying a bleach and water solution during the rainy season until the moss deteriorates and falls off. Let the bleach do the work.

Professional Moss Removal Services in Seattle

If you prefer a professional solution, Chinook Services is here to help. With over 3,000 five-star reviews, we offer a premium roof cleaning service that includes:

• Roof blowing
• Hand gutter cleaning and rinsing
• Bleach soft wash spray to kill 100% of the moss
• A 5-year no-new-moss warranty

Chinook Services Seattle roof cleaning website

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