Algae On Shingles | What It Is & How To Fix It (2022)

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What are algae and how does it form on shingles?

Algae is a type of plant that can grow in both fresh and salt water. It is often found in moist areas, such as on the banks of a river or lake.

Algae can also be found growing on the roof of a house or building. When algae grow on shingles, it can cause the shingles to become discolored and deteriorate.

How Algae Grow And Spread

Algae grow by producing tiny spores that are carried by the wind or water. Once the spores land on a suitable surface, they germinate and grow into new algae plants.

Algae can also spread through contact with other algae plants. For example, if one plant brushes against another, some of the spores may be transferred from one plant to the other.

The Presence Of Algae On Shingles

The presence of algae on shingles can cause your roof to lose its natural coloration & the shingles themselves may start to slowly deteriorate.

Algae feed on the limestone found in most types of shingles. As the algae grow, it produces a black pigment that stains the shingles, & over time, the algae can weaken the shingles and cause them to break down.

3 Prevention Tips

  1. Make sure that your gutters and downspouts are clean and free of debris. This will help to keep water from pooling on your roof, which can provide a perfect environment for algae to grow.
  2. Trim back any trees or shrubs that are close to your house. This will help to reduce the amount of shade that your roof gets, which can also discourage algae growth.
  3. Consider using a zinc strip near the peak of your roof. Zinc strips release zinc oxide when they get wet, which can help to prevent algae from growing.

If you’re considering installing new shingles, look into shingles that are algae resistant.

According to, you should install algae-resistant shingles such as GAF shingles which have a specially formulated granule that inhibits algae growth, keeping your roof looking new for years to come.

3 Treatment Options

If you already have algae growing on your shingles, here are 3 potential treatment options that you can use:

  1. Power wash your roof with a solution of water and bleach. This will kill the algae and remove any stains that it has caused.
  2. Apply a commercial algae-killing solution to your roof. These solutions are available at most hardware stores and home improvement centers.
  3. Hire a professional roofing contractor to clean your shingles. This is usually the best option for removing algae from your shingles, as the professionals have the experience and equipment necessary to do the job correctly.

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