People who live in humid areas may notice unaesthetic dark spots on their roofs. These spots are more common on asphalt shingle roofs.

They can live anywhere as long as there is moisture. These are known as black-greenish algae. Algae can damage the asphalt shingles over time, tends to result in decay, and leaves an unappealing condition.

Having a moldy stained roof neither enhances the looks nor value of the property. So, knowing how to remove mold from roofing shingles is essential for every homeowner.

Mold removal is a comparatively quick and easy task that you may perform on an annual basis or as needed in order to keep your roof weather-resistant and aesthetically pleasing. However, you must exercise caution and adhere to the instructions stepwise to avoid causing damage to your roof.

Read this article to save your roof from molds.

How To Remove Mold From Roofing Shingles

How To Remove Mold From Roofing Shingles: A Comprehensive Guidelines

Whenever mold or blue-green algae grows on the roof, they feed off calcium carbonate and powdered limestone from asphalt shingles. This results in decaying the shingles which causes huge leaking on the rooftop. So, you should remove it before it turns bad enough to affect the roof’s functionality. 

The chemical solution comes in handy to solve this unappealing situation without ruining the arrangement of the shingles. Before beginning the removal process, you should be aware of the necessary items and take appropriate safety precautions. Then, following the instructions, one by one will lead to your achievement.

Required Materials:

The following items are necessary for the task:

  1. Cleaner
  2. Pump sprayer
  3. Garden hose and spray nozzle
  4. Safety goggles
  5. Rubber gloves
  6. Safety rope
  7. Old clothes
  8. Slip-resistant shoes
  9. Ladder

The rest of the article explains the steps to remove the mold in detail.

Step One: Prepare a Cleaning Solution

There are various ways to prepare cleaning solutions. Some people use half chlorine bleach and half water, while others use vinegar or baking soda. 

Professionals recommend powdered oxygen bleach with water among all of these DIY remedies. Because it does not harm the color of the shingles and keeps them aesthetically pleasing.

It also has no negative effects on the vegetation around the house. Wear rubber gloves to keep your hands safe and put on a dust mask, while mixing ¼-part of powdered oxygen bleach with ¾-part of water. The solution should then be gently poured into a pumping spray. 

Spray thoroughly all over the infected roof shingles using the mixture.

Step Two: Wash Down  The Solution

Leave the roof with the solution for 10 to 15 minutes. Allow the solution to soak the mold properly.

Oxygen bleach will start killing them and loosen up from their place. Then it will take away the stain. 20 minutes later, take a long handle soft bristle scrub brush. Lightly brush the shingles.

Harsh scrubbing is not advised. It can lift up the roof shingles from their position. Rinse it off with your garden hose. Don’t use high pressure while spraying on the roof.

Step Three: Examine The Roof

After rinsing off, examine the roof properly to find if there are any more molds left. Sometimes one bleach wash is not enough. Apply more solutions if you have to.

The extra dirty roof might require repeating the process three times. Once clean, rinse it off with a garden hose. It’s really simple.

Safety Tips

You must take some safety measures to avoid additional roof damage while you are doing the job.

First, Roofs are slippery. Wet roofs are more slippery. You should be careful on the roof and wear some sturdy gym shoes that give some traction.

Try to clean the roof when it’s cooler,  in the morning or the cloudy day is the ideal time for cleaning the roof.

Never try to work on an extremely hot and extremely sunny day. It makes oxygen bleach evaporate faster. Not to mention the heat on the roof can cause harm to one’s health.

Be careful if you are trying to clean off algae from your roof.

Do not wash your roof with a pressure washer. Its water pressure is very strong and it can even deteriorate the shingle’s sealant.

The shingle layout is disrupted. They will start losing their quality and appearance as well. Moreover, this can cause a massive leak on the top, causing major loss. Ultimately, your roof is vulnerable and more exposed to fungal growth. 


We all know prevention is better than cure. There are some ways to prevent further mold attacks on your roof.

1. Install Metal Strip:

Once rinsing and cleaning are done, you can set up a sheet of zinc, galvanized or copper-coated at the top. You can choose the metal according to your budget and preference.

Galvanized sheet is substantially cheaper than copper. And Copper is more hazardous to algae. Underneath the shingles, slip the strip.

Leave as much of the sheet visible as possible; the industry norm is to expose one-third of the sheet and fix it with nails and roofing cement to cover up the nail. The same techniques that are used to get rid of and eliminate algae on your rooftop can be used to get rid of moss.

2. Algae Resistant Shingles:

Roofing producers have recently started incorporating copper grains in their production of roof shingles in order to create them algae-resistant.

If you live in an environment where algae can grow in places with high humidity or trees, make sure you get this variety of shingles for your roof. These shingles will increase the lifespan of your roof and save your structure from any sort of harm due to leakage.


I hope you’ve figured out the process of how to remove mold from roofing shingles. Simply follow the instructions accordingly and get your job done. Careful about the water pressure while spraying and do not direct it towards or below the shingles.

It is not recommended to use any hazardous methods. Do not miss any of the steps. If you miss any steps, it will be a problem later on for your roof. Make sure you’re following all safety precautions.

Best wishes and stay safe.


As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

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