DIY Roof Cleaning: How to Clean Your Asphalt Shingle Roof

There’s more than one way to go about roof cleaning. You can use a no-rinse product to get rid of staining or clean the entire roof with a bleach solution. 

Why You Have Dark Spots on Your Roof

roof cleaning

It’s common to get dark spots on your roof in areas shaded by the sun. These spots are caused by algae that thrive in damp environments and feed off the filler in asphalt shingles. Most newer shingles come with an algicide coating, which lasts about ten years. After those ten years, you may notice black or discolored streaks running down your roof’s north and west-facing areas.

The good news is that while it might look bad, algae doesn’t damage your shingles. (Moss and mold can cause damage, though.)

How to Clean Your Roof Stains (Easy, No Rinse Method)

A roof cleaner like Set & Forget kills mold and algae and comes in a far-reach spray bottle that attaches to a garden hose – depending on how many stories your house is, you may be able to clean the roof from the ground. 

The downside to using Set & Forget is that it can take months for the stain to disappear. 

Step 1: Gather Safety Gear

Before using any roof cleaner, you’ll need safety goggles, a respirator mask, and protective clothing. You’ll also need a roof harness and ladder to access the roof safely.

Step 2: Prepare Surrounding Areas

Roof cleaners can damage surrounding plants and furniture. Before you use the product, you thoroughly wet all plants and move your patio furniture out of the way. Another option is to cover plants and furniture with tarps.

Step 3: Apply the Cleaner to the Roof

If you bought the Set & Forget Concentrate, mix five parts water with one part cleaner in a garden spray pump. If you purchased the bottle with a hose attachment, ensure the nozzle is off and then attach your hose.

Take necessary safety precautions before getting on your roof, and note that all areas you spray will become slippery.

Spray the dark stains on the roof, ensuring you’ve coated them evenly. Only use this product if rain or snow is not in the forecast for at least 24 hours. It’s normal for the stains to appear darker after you’ve applied the product.

Step 4: Rinse Plants

If you didn’t cover surrounding plants with tarps, rinse them well.

Step 5: Wait

You don’t need to rinse the roof. The product will continue to work, clearing off algae and preventing it from returning. Depending on their severity and your climate, the stains can take 2-6 months to disappear. 

How to Clean Your Asphalt Shingle Roof with Bleach (Faster Results)

If you’re gearing up to sell your house or are tired of looking at roof stains, waiting up to six months may not be in the cards. Instead, use this method for producing a clean roof without the wait.

The Asphalt Roofing Manufacturers Association recommends washing shingle roofs with chlorine bleach. 

Step 1: Gather Your Safety Gear

Grab some safety goggles, a respirator mask, protective clothing, a safety harness, and a ladder. 

Step 2: Protect Your Plants and Furniture

Bleach can kill your plants and stain upholstered furniture. So before you clean your roof, take the necessary precautions and cover anything under the roofline that you don’t want to damage.

Step 3: Clear Debris from the Roof

Use a broom or a leaf blower to clear debris from your roof before you clean.

Step 4: Apply the Cleaner

In a garden pump sprayer, mix half-liquid chlorine bleach with half water – this is your roof wash. Spray your roof with the solution, focusing on problem spots, and allow the cleaner to sit for 15 minutes.

The bleach needs enough time to kill algae and mold but not enough time to dry to the surface.

Step 4: Rinse with a Garden Hose

After 15 minutes have elapsed, rinse the roof with a garden hose. Rinse well to rid the shingles of excess bleach.

Do not use a pressure washer to clean or rinse your asphalt shingle roof. Even lower pressure is enough to rip the shingles from the roof and cause leaks.

How to Maintain Your Clean Roof

Once you’ve cleaned your roof, keep it in good shape by implementing a simple maintenance routine.

  • Keep tree branches trimmed. Tree branches shade your roof, causing ideal spots for algae and moss to form. Keep large tree branches trimmed back and away from your roof.
  • Ensure a well-running gutter system. A proper gutter system keeps water flowing away from the roof and foundation of the home. Be sure to clean your gutters as needed.
  • Keep debris off the roof. If you live in an area where sticks and leaves fall on the roof, remove them with a leaf blower and broom as needed.