How to Remove Algae and Mold From Roof Shingles

Your roof’s health and condition will contribute to the appearance of your house. In humid climates, such as West Michigan, the moisture can cause black streaks of algae to appear on your roof. This makes it look dirty. There are several steps you can follow to maintain the strength of your roof, your home’s look, and its resale price.

What is the difference between Algae, Moss, and Mold?

The organisms that grow on your roof are quite different. They all love moisture.


In West Michigan, we are most likely to see the black, flat streaks that algae leave on roofs. Roof algae are most commonly gloeocapsa Magma or blue-green algae. Gloeocapsa Magma, an alga that can spread by air or animals, can grow in size from a tiny spot to a long streak within a few months. According to the Asphalt Roofing Manufacturers Association (Arassing Roofing Manufacturers Association), the algae may not be harmful to asphalt shingles, but it can certainly make a roof look unattractive.


The moss plant is non-vascular and fluffy, compared to the algae. It can appear in green, grey, or blue. Moss is usually found in damp and shaded places, such as on roofs that face north or are shaded. It is not harmful to humans but can cause your asphalt shingles to curl.


Mold can be caused by spores carried by the wind or tracked by birds and squirrels in the neighborhood. Mold spores are most likely to take hold on roofs that have already been moistened, such as around chimneys and in places where moss is already damaging the shingles.

Roof Moss and Stains: How to Remove Them

You can remove algae from your roof using a simple procedure that involves bleach and water. A spray bottle, a garden hose, and a ladder are all you need.

When to Clean Your Shingles

A sunny day can cause the cleaning solution to evaporate too fast, so it is best to clean your roof on a cloudy or rainy day.

Prepare Your Solution

Several chemical products are available at the hardware store to remove algae. It is also possible to use chemicals that you have in your home to remove moss and algae, such as bleach or oxygen bleach. Mix water and laundry-strength oxygen or chlorine bleach 50/50 and spray it on with a sprayer. Add 1/2 cup of trisodium chloride per gallon to make a stronger cleaning solution.

Roof Safety

When working on a rooftop, keep in mind that they can be dangerous. This is especially true when they are wet. Avoid steep slopes and wear a safety harness or slip-resistant footwear. Wear eye protection as well to protect your eyes from chemicals.

Protect your home and plants

Your plants around your home will not like bleach either, just as your roof organisms won’t. Spray your plants, trees, shrubs, and lawn with water to minimize damage. You might even want to cover the plants with plastic sheets. When you are finished, you should spray the plants one last time to remove as much runoff as possible.

Roof Algae & Moss Removed

Spray the bleach solution on your roof and allow it to rest for about 20 minutes. The roof can be damaged if you leave the bleach solution on for too long. Rinse the roof using the hose after the solution has done its work. The rinse water will likely remove the majority of the algae and moss. Even though some moss remains, it will continue to wither with rain.

Roof Stains: What to Avoid

Although it may be tempting, using a high-pressure washer can strip the asphalt shingles of their granules, leading to premature roof wear. You can repeat the process if you find that you still have algae or moss on your asphalt shingles after cleaning them. If you are using bleach, make sure that the solution is completely rinsed.

How to Remove Roof Mold

Roof mold is more difficult to remove than algae or moss. You can use a similar method to remove stains and mold. However, there are often deeper problems. Roof mold can be identified by an attic and roof inspection. Black mold can be harmful to your health, and roof damage could be a sign of something bigger. It is best to leave mold removal to professionals who know how to remove black mold from asphalt shingles.

This post was written by a professional at A Buff & Beyond Pressure Washing. With A Buff & Beyond Pressure Washing in Port Saint Lucie, FL, you can get your home looking as good as new. A Buff & Beyond Pressure Washing provides the highest-rated and best quality pressure washing services in the area and can help your beautiful home beat the chaotic Florida elements. Services offered by A Buff and Beyond include house washing, paver sealing, and roof cleaning Rio FL. A Buff & Beyond Pressure Washing wants to wash and beautify your home as much as you do, and when you call A Buff & Beyond, there is no robot or machine. Instead, customers get a fast and honest quote, years of expertise, a safety-conscious team, and are always on time. So when you need roof cleaning, paver seal, or pressure washing service to restore your home, contact A Buff and Beyond today to get started.

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