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The Best Way To Remove Moss and Algae On Your Roof

Date: June 22, 2024

Have you ever noticed that green or brown growth on your roof? Moss or algae, these organisms not only affect the aesthetics of your home but can also pose a significant threat to the durability and longevity of your roof. Moss and algae might look nice on an old, weathered roof, but you don't want them sticking around. This is especially true if you live in a rainy area or have asphalt shingles.

In this article, we will explore the best way to remove moss and algae from your roof, understand how these growths damage your roof, and learn effective methods to prevent them.

What Is Moss and Algae

Moss is a common organism that can take root on your roof, particularly in Vancouver’s climate. It thrives in wet and humid conditions and can cause significant roofing issues if not removed.

Algae is another organism that may appear on your roof, especially in damp and humid environments. If left unchecked, it can lead to serious problems with your roofing.

How to Spot Moss on Your Roof

Moss might not be immediately visible from the ground, but there are ways to get a closer look. Binoculars or even a drone with a camera can help you inspect your roof more thoroughly. When examining your roof, be sure to inspect every area, especially those that remain shaded for extended periods. Additionally, pay attention to any signs of discoloration or irregularities on the surface, as these could indicate the presence of moss or algae. Regular inspections and early detection can help you address moss growth before it causes any significant damage to your roof.

What Does Roof Moss and Algae Look Like?

The Best Way To Remove Moss and Algae From Your Roof

Identifying roof moss is fairly straightforward. It typically appears as green, fuzzy growths between shingles or on metal roofing surfaces. Additionally, you might notice the presence of algae, which manifests as black spots on the roof's surface. Another possible indication of roof moss is the presence of lichens, which resemble green plaques that can vary in texture, appearing either flat or textured. Regularly inspecting your roof for these signs can help you detect and address moss growth before it leads to more significant issues.

Why You Shouldn’t Ignore Moss And Algae

Call experts to remove moss from your roof as soon as you see it. While moss isn't a health risk like mold, it can damage your shingles and might lead to needing a roof replacement. The most common issue with moss, however, is that it reduces your home's curb appeal.

Some power washers claim that moss and algae are "eating" your roof. While this is somewhat true, it takes a long time for them to affect your shingles' performance. However, they do make your roof look unattractive, which is the main reason people clean their roofs.

Moss can also block your gutters and prevent proper drainage in your home. Hiring a moss removal service is the best way to solve these practical and aesthetic problems.

Roof Safety Tips

Working on a roof can be dangerous. Wear protective gear such as work boots, thick pants, and a hard hat or helmet. Ensure your harness is in good condition and properly anchored. It's also important to have someone with you to hold the ladder or call for help if needed.

Getting Ready to Remove Moss

Preparing to remove moss from your roof is straightforward. Make sure you're wearing proper safety gear, your ladder is sturdy, and your safety harness is correctly installed according to the manufacturer's instructions.

Steps To Remove Moss And Algae From Your Roof

  1. Remove Loose Moss Using a garden hose with a gentle spray, wash the roof downward to dislodge moss. Avoid spraying against the roof's grain to prevent lifting shingles or pushing moss underneath. Collect dislodged moss in a trash bag for disposal.
The Best Way To Remove Moss and Algae From Your Roo
  1. Gently Scrub Remaining Moss Scrub the roof cautiously to avoid damaging shingles. Use a long-handled brush, working from the top down to prevent lifting shingles. Work slowly and avoid excessive scrubbing to prevent asphalt shingle granule loss.
The Best Way To Remove Moss and Algae From Your Roof
  1. Apply Moss Removing Solution Choose a commercial moss removal solution with ingredients like potassium salt of fatty acid or zinc sulfate. Mix as directed on a cloudy day and apply from the top down, ensuring not to lift shingles. Follow package instructions for rinsing if necessary.
  2. Install Metal Strips Attach 2-to-4-inch wide copper or zinc strips below the roof ridge on both sides using roofing nails. These metals discourage moss growth, and as they oxidize with water, they help prevent moss and algae growth. Overlap sections by at least one inch across the entire affected area for continuous coverage.

Getting Professional Help vs. Doing It Yourself

While attempting to remove moss and algae by yourself is an option, it's crucial to proceed with caution. Rushing or being careless during the process can lead to damage to your roof. This damage might be more expensive to repair than hiring a professional roofer in the first place. Additionally, roofing experts have the knowledge and experience to effectively remove moss and algae without causing harm to your roof. They also have access to specialized equipment and cleaning solutions that may not be available to the average homeowner. Hiring a professional can save you time, effort, and potentially costly repairs in the long run.

Preventing Moss Growth on Your Roof

To prevent moss from growing on your roof, it's essential to ensure that sunlight can reach it. Trimming overhanging tree branches not only promotes sunlight exposure but also safeguards against storm damage. Additionally, keeping your gutters clean is crucial for maintaining proper water drainage from your roof, which can further inhibit moss growth. Moreover, installing metal strips along the peak of your roof on both sides can be an effective long-term solution to deter moss from taking hold. Regular maintenance and these preventative measures can help keep your roof moss-free and in good condition for years to come.


Moss and algae growth on your roof not only affect the appearance of your home but can also cause significant damage if left unchecked. It's important to regularly inspect your roof for any signs of moss or algae and take prompt action to remove them. Whether you choose to tackle the removal yourself or hire a professional, safety precautions must be followed to prevent any further damage to your roof. Additionally, implementing preventive measures such as ensuring sunlight exposure, keeping gutters clean, and installing metal strips can help deter moss growth in the future. By taking these steps, you can maintain the durability and longevity of your roof, ensuring it remains in good condition for years to come.

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