It isn’t always surprising when you realize that mold, mildew, or moss has grown to a certain level on your asphalt roof shingles. In fact, this is a common occurrence in areas with high humidity.

However, when this buildup increases, it is always a great idea to clean it off the asphalt roof shingles. But how can you do this?

It is always preferable to use equal amounts of water and bleach to clean your asphalt roof shingles. After mixing them, use a sprayer to apply the mixture to your asphalt roof shingles. You will have to wait for a few minutes before rinsing with clean water. Always spray with low pressure to avoid damaging your asphalt roof shingles.

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How To Clean Your Asphalt Roof Shingles

Clean Asphalt Roof Shingles

There are several ways to clean your asphalt roof shingles; however, all these depend on the material or growth.

For instance, it would require a certain amount and type of bleach to clean mold off your asphalt roof shingles. Also, you would need a completely different material and process to clean off mildew.

The most popular and effective way of cleaning asphalt roof shingles is by using chemical substances such as chlorine bleach.

However, the growth and material that creates this dirt are always bound to recreate it even after cleaning it. 

And while it may take some to for the dirt to return, other chemicals and conditions prevent its recurrence for a more extended period.

So, cleaning your asphalt roofing with chemical substances once in a while may not damage the roof. However, frequent application of these chemicals will cause ultimate damage.

So, several substances such as bleach, trisodium phosphate, and water create the perfect effect in cleaning your asphalt roof shingles.

Also, if you’d prefer more mild substances that pose the barest harm to your roof, oxygen bleach should be your option.

To effectively complete the cleaning process, you should use a pump sprayer to apply the chemical mixture to the asphalt roof shingles. However, ensure to apply these at low pressure to prevent damage to the roof shingles.

Nonetheless, it is always better to clean your asphalt roof shingles on a cloudy day to prevent the chemical mixture such as bleach from evaporating.

Evaporation would prevent the substances from acting on the dirt material, thus interrupting the process.

How To Clean Mold Off Asphalt Roof Shingles?

Mold materializes on your asphalt roof shingles as dark stains or streaks. And although this is a more common occurrence in warm, humid environments, it can happen in any other environment. 

For many people, cleaning mold off asphalt roof shingles is a painstaking process. For this reason, many people prefer to employ roofing personnel with a lot of experience to do the job for them.

Nonetheless, if you’d love to do this by yourself, the first thing to do is protect your property close by and gather the needed materials and equipment.

To do this, you should use a plastic covering or a tarp to shield furniture, plants, and other stuff exposed to the cleaning solution you’re about to spray.

From here, use this simple procedure to complete the process:

#1. Spray A Solution Of Bleach On The Roof Surface

Create a mixture of bleach and water in a 1/4  ratio, then add a full teaspoon of trisodium phosphate to the bleach solution. Transfer this mixture into a sprayer and apply it to the roof with care.

#2. Rinse-Off the Bleach Solution

After waiting for about 30 minutes, use a garden hose to rinse the bleach off the roof shingles. Here, ensure to put on your rubber soles shoes and your gloves to prevent contact with the bleach. 

How To Clean Mildew Off Asphalt Roof Shingles? 

If there is persistent mildew growth on your asphalt roof shingles, the best option will be to clean it off using chlorine bleach. But first, dilute the bleach in water using a 1/1 ratio.

Then, spray this mixture on the asphalt roof shingles and wait for over 20 minutes. 

This wait time can be longer, depending on the degree to which the mildew has infested your roof. However, do not let the bleach dry on your roof shingles as it would hinder proper cleaning.

From here, rinse the roof with water at low pressure. 

Always protect the nearby furniture and shrubbery from coming in contact with the bleach. Also, use the proper protective gear when carrying out this process. 

With time, the ensuing rains will eventually wash off the rest of the mildew. However, you may require more than one cleaning session to deal with this mildew completely.

But always avoid using a pressure washer as it can accelerate the roof’s failure.

How To Clean Moss Off Asphalt Roof Shingles?

Like mildew and mold, moss can readily grow on your asphalt roof shingles. And this can be quite challenging to clean, given that moss engraves its roots within the frames of your roof surface. 

However, a combination of several steps can aid you in achieving this in next to no time:

#1. Access The Moss-Infested Roof Using a Sturdy Ladder

You’ll need a suitable place to hold onto while you work to clean your roof. So, a steady and sturdy ladder is what you should go for.

But do not forget to put on your protective clothing, rubber-soled shoes to hold you against slipping, and some glasses. Also, ensure to affix yourself to the building using a rope.

#2. Scrub Off The Moss

You can do this using a soft brush with standard bristles. This would allow you to clean the moss without damaging the roof. 

#3. You Can Employ Chemical Cleaning Agents

If scrubbing does not take off the moss on your asphalt roof shingles, you would have to use some cleaning agents on it. Bleach is a great choice and pulls off the moss with minimal scrubbing.

What Is The Best Product To Clean Roof Shingles?  

There are several conflicting opinions regarding the best products for cleaning roof shingles. Read more to know how to separate the roof shingles.

However, several tested products always stand tall over others; here are they:

#1. Sodium Hypochlorite/Bleach

This is one of the most utilized roof cleaning products. Its popularity does not only come from its use in cleaning roof shingles but for cleaning many aspects of the home. 

Adding some detergent to this product accentuates its cleaning effect on your roof. First, however, ensure to protect yourself from exposure. It is best to apply another coat if it doesn’t clean perfectly at first.

#2. Sodium Percarbonate/Oxygen Bleach

This is a relatively safer option compared to bleach despite its lesser effectiveness. Nonetheless, it is an excellent option for people with sensitive plants prone to harm.

OxiClean is one reliable brand of this product. It may be slow, but it is worth it in the long run.

#3. Hydrogen Peroxide

Hydrogen peroxide is more friendly to the environment as compared to bleach. So, for this reason, many people prefer it. However, it is more expensive and a little less effective.

But when picking hydrogen peroxide for cleaning your roof shingles, go for ones with concentrations of 15% or higher. 

#4. Trisodium Phosphate and Sodium Hydroxide

These are degreasers that thicken your cleaning solution and make them stick better during the cleaning process. This allows you to access the thick patches of moss, mildew, or dirt with more ease.

The downside of using this is their paint stripping properties. You can order trisodium phosphate.


To a certain point, cleaning your asphalt roof shingles will become the ideal thing to maintain your house’s aesthetic value.

So, using the right processes and substances to clean the dirt, moss, mildew, and mold is key to maintaining the quality of your roof.

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