Though you might pay more attention to your home’s interior, the exterior condition is just as crucial. We understand how difficult it can be to stay on top of certain problems like mold when it appears in out-of-the-way places such as your home’s roof, but just because it is out of the way doesn’t mean it’s not dangerous.

The Dangers of Mold on Your Roofing Shingles

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Mold forms when moisture dwells on your roof’s surface. The process usually begins with the formation of small spots that transform into streaks on your roof’s plane. Furthermore, mold spreads exceptionally quickly.

According to All Dry USA, mold takes only 48 to 72 hours for it to spread to your home’s interior. Here are some of the dangers of mold and why you need to clean mold off roofing shingles.

  • Unattractive Streaks that detract from your home’s beauty, taking away its curb appeal.
  • Mold becomes slippery when wet, creating a safety hazard when climbing on your roof for cleaning, maintenance, or leak inspections.
  • Mold weakens your roof, deteriorating the condition of the shingles, causing roof rot, and shortening your roof’s life span.
  • Most importantly, mold can be a health hazard to you, your family, and pets if left untreated.

Because of these and many more potential dangers, it’s essential to take care of mold as soon as possible.

How to Clean Mold off Roofing Shingles

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You can clean mold off roofing shingles using your basic household bleach. Here’s how to go about it:

Safety First

Before you begin, take all the necessary safety precautions. These safety precautions include:

  • Dressing appropriately and wearing safety gear, such as thick rubber gloves, eye protection, and a breathing mask or respirator.
  • Covering surrounding vegetation to prevent runoff from the cleaning solution from being absorbed and causing damage.

You must also be careful when climbing onto your roof. Use a sturdy ladder and ensure the spot you place your ladder grants you unobstructed access to your roof. If you have a large roof, you might want to invest in a safety harness.

Scrub the Thickest Buildup

Once you’re on top of your roof, scrub the surface of the shingles to loosen the mold that has stuck. Pay more attention to the areas that are hard to reach and those with the heaviest mold growth. Wear your breathing mask while doing this to avoid inhaling the mold particles you brush off.

Mix Your Cleaning Solution

Chlorine bleach is an effective solution for getting rid of the mold. You can buy it or choose to mix some up at home by mixing one quart of bleach, a gallon of water, and a quarter cup (60 ml) of trisodium phosphate.

Spray Your Roof

To facilitate maximum coverage, use a pump sprayer when dispersing the solution. Avoid using a pressure washer because the force of the water could damage your shingles.

Spray your entire roof, starting on the lowest row and working your way backward to prevent the chemical solution from draining in your direction.  Keep spraying until you see runoff, allowing the solution to soak for about 20 minutes.


According to Jeff Guthrie, a Phoenix Roofing Repair specialist, bleach can cause permanent discoloration or damage to your roof, so rinsing the solution is vital. Once you’ve left the solution to soak for approximately 20 minutes, take your garden hose, or fill your sprayer with fresh water, and rinse the areas containing the cleaning solution. Begin at the top shingle and make your way downwards to prevent water seepage.

Editorial Contributors
Matt Greenfield

Matt Greenfield

Matt Greenfield is an experienced writer specializing in home improvement topics. He has a passion for educating and empowering homeowners to make informed decisions about their properties. Matt's writing focuses on a range of topics, including windows, flooring, HVAC, and construction materials. With a background in construction and home renovation, Matt is well-versed in the latest trends and techniques in the industry. His articles offer practical advice and expert insights that help readers tackle their home improvement projects with confidence. Whether you're a DIY enthusiast or a seasoned professional, Matt's writing is sure to provide valuable guidance and inspiration.

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