How to Clean Roofing Shingles—3 Easy Solutions

As a proud homeowner, you want your roof to look like it does in home improvement magazines and TV shows: shiny and free of debris and unsightly grime. But often, nature has other plans in mind. Overhanging branches, heavy rainstorms, and excessive moisture can all leave your home’s covering in bad shape.

In this article, we’ll discuss three methods to clean a roof and provide tips on preventing future grime buildup on your roof shingles.

1. Bleach & Water to Clean Your Roof

Have you noticed black streaks distracting from the beauty of your roof? These blemishes usually indicate the presence of blue-green algae. If the stains appear to be lighter in colour, you likely have green colonies of moss growth.

Luckily, you can use a solution of laundry-strength chlorine bleach and water to fight off these stubborn moss or algae stains:

  1. Mix equal parts of water and bleach to create your cleaning solution.
  2. Pour the solution into a garden sprayer. Make sure to pick a garden sprayer that can withstand harsh chemical compounds.
  3. Once you’re on the roof, wet the surface with the sprayer. Allow the solution to sit for 15 to 20 minutes.
  4. Scrub the area to attack the streaks more aggressively. Once you finish, rinse the area using a garden hose with low pressure.

Warning: A  bleach solution could stain your asphalt shingle roof if you apply too much at once or don’t wash the liquid off properly.

2. Roof Cleaning Products for an Asphalt Shingle Roof

Bleach can be corrosive and unpleasant to work with, so you can opt for a roof cleaner to do the job instead. A professional-grade cleaning product will target roof algae, like Gloeocapsa magma. Plus, you won’t have to mix anything yourself.

These cleaning products contain chemicals like sodium hypochlorite that lift deeply-set discoloration. While sodium hypochlorite isn’t as strong as bleach, you should still exercise care when handling it:

  1. Wear protective gloves and goggles to protect your skin and eyes.
  2. Use the cleaner bottle to spray your roof until the asphalt surface is thoroughly wet.
  3. As with the previous method, you should let it soak on the algae stains for about 15 to 20 minutes.

There isn’t a single type of roof cleaning product on the market. So, one could work better for the particular spores you have than another. The only way to find the best product for your circumstances is through trial and error. We recommend experimenting with multiple products to figure out what works for your roofing.

3. Pressure Washer for Asphalt Shingles

Some homeowners wish to steer clear of any chemical products, as they fear staining their asphalt shingle roofs. If you fall into this category, you can use a pressure washer instead.

Professional roof cleaners will charge hundreds of dollars to pressure-wash roofs. While you could cough up the money for this service, it isn’t necessary. If you don’t have this piece of equipment on hand, you can borrow one from a neighbour or rent one for a low cost. Then, you’ll have to dedicate an hour or two of your time to get the job done.

Keep in mind that a regular hose won’t be enough — a pressure washing machine will produce a pressure of 2,000 pounds per inch or more.

  1. Ensure your asphalt shingle roof doesn’t have any loose pieces before you try this method.
  2. Start by setting up your machine to a clean plumbing source.
  3. Spray the affected areas until the stains start to dissipate due to the high force.

Final Roof Cleaning Tips

After you finish the roof cleaning process, you should take preventative measures to prevent algae from coming back. For example, cut away any tree branches that are touching your roof or blocking sunlight. If you allow these branches to hang around, you’ll promote moss and algae growth.

It would be best if you also made an effort to go on top of your roof and clear the gutters of debris. Use a battery-powered leaf blower for convenience. The whole process shouldn’t take too much of your time, and it’ll promote adequate drainage and prevent algae and moss from growing.


What can you use to clean your roof shingles?

You can use many products and methods to clean your roof shingles, including chemicals like sodium hypochlorite and force from a pressure washing machine.

Should you clean your asphalt shingle roof?

Yes. However, it would be best if you didn’t do so too often. Climbing onto your building to clean your roof too frequently can loosen the roofing shingles’ granules and leave the roof covering exposed to the elements.

How do you clean dirty asphalt shingles?

Learning to clean a roof is a process. Determine what grime your asphalt shingles are prone to developing (moss, algae, etc.). Your covering may only need water and some scrubbing to uplift the discoloration. However, more stubborn stains will require harsher chemicals or excessive force.

Will bleach damage roof shingles?

Bleach is an effective cleaning solution that shouldn’t damage asphalt shingle roofs. However, you should always rinse away your mixture thoroughly to ensure the liquid doesn’t leave behind lasting damage.

From customization to high-quality service, our team at T. Simpson Roofing Ltd. will always have your best interest in mind.

If you are interested in learning more about your roofing options, click here or call 1-800-925-3044 for more information.  

T. Simpson

Originally founded by a 16-year-old Tony Simpson as a way of acquiring funds to help pay his way through university, T. Simpson Roofing, propelled by Tony’s strong work ethic and commitment to delivering quality work and unbeatable customer service, quickly grew into a thriving business.

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