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How To Clean Roof Shingles Without Damage

How To Clean Roof Shingles Without Damage?

Have you ever noticed that when you look up at your roof shingle, it’s covered with black stuff such as mold, mildew, moss, or soil which makes the appearance of your house dirty?


Good news! You can you do it yourself by using the correct roof-cleaning products and the correct tools for the job.

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How To Clean Roof Shingles Without Damage?

Have you ever noticed that when you look up at your roof shingle, it’s covered with black stuff such as mold, mildew, moss, or soil which makes the appearance of your house dirty? Do you want to get your roof shingles cleaned by a professional? Perhaps you are D.I.Y. person or an aspiring professional?

Good news! You can you do it yourself by using the correct roof-cleaning products and the correct tools for the job. Don’t worry as Commercial Cleaning of San Diego has you covered, regardless if you choose our shingle cleaning service or you want to do it yourself!

Read on below to see our “Pro Tips” for you to use on your next project so you can see how to clean roof shingles without damage.

Before AND After – Experience the Difference!

What causes black streaks on roof shingles? 

Black streaks and stains on roof shingles are most commonly caused by gloeocapsa magma, fire moss, mildew, lichen, mold, etc. They usually appear as blue-black or green-black stains. 

There are two specific types of algae growths on Asphalt roofs such as; 

Gloeocapsa magma

Gloeocapsa magma grows best in environments where there is less sun exposure throughout the day in a warm, humid environment. Gloeocapsa magma is the most organic growth on Asphalt roof shingles.

It degrades the limestone of the roof shingles and makes the whole roof shingle completely black if left untreated.

Fire moss

Fire moss is less common on roof shingles as compared to Gloeocapsa magma but it still grows on cedar shake and Asphalt roof shingles.

If the fire moss covers your roof shingles completely then, it will allow the water to seep inside your house which severely damages the roof.

There are four specific types of organic growth on metal roofs other than gloeocapsa magma such as;


Lichen roof growths are a combination of algae and fungus. They are very difficult to remove as they bind to the metal roof shingles firmly and tightly. 

Lichen growths on metal roof shingles can even cause rust on the metal roof surface and can also damage the roof’s composition.

Roof moss

Moss is also similar to lichen as it also binds to the surface tightly due to its strong root structure. 

Moss and lichen team up with each other and create a powerful organic super growth on the metal roof shingle making it difficult to remove.


Mold is a stinky, unhealthy plant growth seen on roof shingles. Mold growths are very slippery and have an unpleasant smell.

Mold is hydrophilic (water-loving) in nature, so it grows best in areas that have a rainy climate.


Mildew is somewhat identical to mold as it also flourishes in wet, rainy areas. Mildew has a powdery appearance on roof shingles and it has a wide color spectrum ranging from pink to dark black. 

Asphalt shingles washing 

The best way to clean an Asphalt roof is by using the right amount of shingle-cleaning chemicals, and a low pressure should be used to maintain the lifespan of Asphalt roof shingles. This process is known as soft washing in the roof-cleaning industry.

Asphalt shingle roof wash with bleach

12.5% Sodium hypochlorite (pool shock) is the most commonly used algae ide for shingle washing in the roof-cleaning industry. The ratios that can be used for washing shingle roofs are as follows;

  • 75% sodium hypochlorite – 25% water: This shingle-cleaning mixture is most effective for removing any kind of hearty algae, fire moss, lichen, etc.
  • 50% sodium hypochlorite – 50% water: This ratio of shingle cleaner is best suited for black streaks caused by gloeocapsa magma or light black algae.
  • 25% sodium hypochlorite – 75% water: The diluted chemical for washing shingle roofs can only be used for eliminating lighter black stains caused by gloeocapsa magma. This chemical mix can not be used for removing stubborn stains as it contains a high concentration of water.

Asphalt shingle roof cleaning solution | Step-By-Step

  1. Pre-soak the plants with water to saturate the plant cells and prevent the shingle cleaner from penetrating the plant cells. 
  2. Mix the chemicals in a 50:50 ratio to prepare the perfect shingle cleaner for Asphalt roofs.
  3. Drip the shingle cleaner from top to bottom to ensure an even application for washing the shingle roof perfectly. Moreover, only use a small amount of shingle cleaning chemical first as less is more. 
  4. If the algae or fire moss does not disappear or turns white, apply a second coat of shingle cleaner to ensure that the dirt is removed completely. 
  5. Rinse the plants after the shingle roof washing treatment. 
  6. The shingle cleaning chemical does not need to be rinsed with water. Reapply the chemical if any black dirt is left over the roof shingles.

Metal shingle roof wash

Using a low-pressure washer is the best way to clean a metal roof as high pressure can damage the structural integrity of a metal roof causing it to leak.

Metal shingle roof wash

The active ingredient used for the effective cleaning of metal shingles is sodium hypochlorite as it has an excellent cleaning action. Sodium hypochlorite is mixed with water in different ratios for washing shingle roofs such as; 

  • 5% sodium hypochlorite – 95% water: This diluted shingle cleaning chemical can be used for cleaning metal roof shingles without any damage or impairment. Moreover, a soft bristle brush can also be used to remove the organic growth by scrubbing to improve the efficacy of diluted shingle-cleaning chemicals.
  • 10% sodium hypochlorite – 90% water: If the first option does not work for effective shingle roof wash then, this chemical mix ratio can be used and a soft bristle brush should be used along with it for brushing off the organic growths from the metal roof shingles.
  • 20%-50% sodium hypochlorite – 80%-50% water: This chemical mix ratio should only be used by a professional for shingle roof wash as it has a high ability to damage and impair the metal roof structure by oxidizing and rusting it.

Metal shingle roof cleaning solution | Step-By-Step

  1. Cover the plants in your garden or constantly water them during the process of washing shingle roofs.
  2. Mix the metal shingle roof washing materials by using a blender or mixer and transfer the effective shingle cleaner to a pump sprayer. 
  3. Wet the entire metal roof shingles with water to saturate the pores of the metal shingles for better roof shingles washing. 
  4. Apply the least amount of shingle cleaner on metal roof shingles and use a soft bristle brush for scrubbing. Repeat the same process until the metal shingles are completely cleaned. 
  5. Lastly, wash shingle roofs using water and also, rinse everything that is surrounding the roof.

The Pros and Cons of Washing Shingle Roofs

The Pros of Washing Shingle Roofs:

There are many advantages of washing shingle roofs such as; 

  • Keeping your roof shingles in a good condition will increase the lifespan and longevity of the roof.
  • Shingle roof wash will make your bungalow look more polished and elegant. 
  • Washed roof shingles will also increase the curb appeal of your property as potential buyers tend to look at the roof first. 
  • Shingles washing will prevent your roof from deterioration and damage from harsh weather conditions. 

The Cons of Washing Shingle Roofs:

There are many drawbacks of washing shingle roofs without professional help such as; 

  • If you wash roof shingles yourself by scrubbing them with a brush or treating it roughly then, the shingle granules can be displaced which severely decreases the lifespan of the roof. 
  • Expensive roof-cleaning equipment and tools are needed for effective shingle cleaning which does not damage or deteriorate the roof shingles.

The Bottom Line

Roof shingles cleaning is very necessary as the algae or other organic growths can severely affect its lifespan.

Commercial Cleaning of San Diego uses the best shingle roof cleaning solution for your roof shingles and the most professional roof-cleaning services. We also have roof-cleaning guides and tutorials to offer additional help to their customers. 

So, what are you waiting for? Contact us today and we will be more than happy to assist you.