Essential Tips for Removing Unsightly Roof Stains

May 7, 2021
Tips for Removing Roof Stains

Essential Tips for Removing Unsightly Roof Stains 

If you’re a homeowner, chances are you pay close attention to your home’s yard and exterior appearance. But what about your roof? Over time, your shingles can become weathered and damaged. Some homeowners are shocked to find dark, unsightly stains on their roofs.

If you’re one of those homeowners, there are many tips and tricks for removing these stains without necessarily having to make costly roof repairs. In this post, we’ll help you better understand the problems that cause these unsightly roof stains. We’ll also walk you through some basic do-it-yourself methods you can use to keep your home beautiful and lengthen the lifespan of your roof. 

Understand the Problem

Large dark streaks on your roof are usually caused by the growth of blue-green algae. This organism is airborne, but humid conditions, shade, or moisture on your roof can encourage their growth.

Algae growth isn’t typically something to be concerned about, though it does result in cosmetic damage. There are cases where algae growth may indicate some residual moisture problems, which can indeed cause damage over time. If you’re concerned your roof may be suffering from moisture damage, contact a local roof repair service who can help determine any underlying problems.

Plan Before You Clean

Before you dive right in, you might want to do some planning to ensure you don’t cause further damage to your roof or endanger your health and safety. 

Does Your Attic Indicate You Need Roof Repair?

Check your attic for cracks and leaks. If you can see sunlight through any of the boards of your roof that means you have a leaky roof. You’ll have to delay any cosmetic improvements until you address the structural issues on your roof, which are not issues you can fix yourself. Contact a local roof installation company to repair the damage before moving forward. 

Safety First

When working on a roof, always wear shoes with good traction, and consider using a safety harness for added protection. If you’re working with chemical cleaning products, it’s best to also use gloves and safety goggles to protect your skin and eyes. 

Protect Your Plants

If you use chemical cleaning agents, you may want to prepare any surrounding shrubbery by spraying them with your garden hose. This layer of moisture will protect them from chemicals that run off the side of your roof. If you have nearby lawn furniture, it’s best to move these items out of the way to prevent damage. 

Make Sure Your Gutters Are Clean

Because dirt will be coming off the roof, make sure your gutters are cleaned and unobstructed. That way any runoff can be channeled safely away from your home through your roof’s drainage system.

Save time and call the professionals at Kanga Roof to make sure your gutters are spotless.

Consider Roof Replacement

Algae growth may be just the tip of a much larger iceberg. The amount of moisture that contributes to algae growth and ugly stains has the potential to strip your shingles of their natural water-resistant properties—if it hasn’t already. In this case, they’ll need to be replaced. 

Additionally, you may consider purchasing algae-resistant shingles that will prevent this problem from happening altogether.

Choose the Right Chemical Cleaner for Your Roof

Once you’re ready to clean your roof, you’ll be relying on a combination of physical and chemical methods to remove the stains. But how do you choose which chemical to use? 

Bleach Roof Cleaner Recipe

Some homeowners may wish to mix their own cleaner using bleach. If you go this route, follow the simple “recipe” below:

  • 1 quart of bleach (6% sodium hypochlorite)
  • 1 gallon of water

You can add more bleach if desired, but you should generally avoid anything higher than a 50-50 mixture of bleach and water. You may add 1/4 cup of TSP (trisodium phosphate) if you want a stronger cleaning product.

Under no circumstances should you add any cleaning product that contains ammonia. This can result in a dangerous poison gas. 

Environment-Friendly Commercial Cleaners 

Unfortunately, bleach can be toxic and corrosive, and it’s not great for the environment. Many roofing experts even recommend you avoid these products altogether, as caustic chemicals can actually further any damage to your roofing tiles.

Today, there are many commercially available cleaning agents you can purchase. For example, DEFY Roof Cleaner is a safe, non-corrosive cleaner available at many hardware stores.

Proper Roof Cleaning Techniques

Once you’ve selected your preferred cleaning product, it’s time to clean your roof. Here are some steps you can follow for a thorough cleaning:

Mix Your Cleaning Solution in a Pump Sprayer

Prepare your cleaning solution ahead of time by mixing the desired ratio in a pump sprayer. Leave this on the ground until you’re ready, which will keep you from juggling too many tools during the next step.

Clear Away any Debris

If you have moss growth or other debris on the surface of your roof, you can clear it away with a broom or a leaf blower before using any liquids.

Soak the Affected Area with Water

You can use your garden hose to soak the darkened area with water. Some roofing installation websites recommend using a power washer on its lowest setting, but we recommend you avoid any sort of high-pressure tools. These can damage or chip tiles and cause further harm to your roof as you clean.

Spray the Affected Area with Cleaner

Now you can bring your pump sprayer to the roof. Spray the affected area with your cleaner. You should use enough cleaner that you notice it beginning to run off. 

Use extra caution during this step. Slippery chemicals can make it easier to lose your balance and fall.

Let the Cleaner Sit for 20-30 Minutes

If you purchase a commercial cleaner, the manufacturer may have specific instructions. But generally, you should let the cleaner sit for 20-30 minutes, which gives it time to loosen dirt and remove the stain.

Rinse the Area with Water

Use your garden hose to rinse the area with water. If the algae growth is stubborn, you can use a stronger hose nozzle to try and dislodge it, though we still recommend avoiding high-pressure sprayers that can damage roofing tiles. 

Preventative Maintenance

Keep your roof looking clean by preventing algae growth from occurring. The best way to do this is to have a professional install metal in strategic places on your roof. This will also save you major money down the line.

You don’t need to have your entire roof covered in metal. A local roofing contractor can install narrow strips of sheet metal on each side of your roof just below the ridge. Every time it rains, the water will carry metal particles (from what’s installed) over your shingles and form a protective barrier.

Experts will likely use copper or zinc as these metals are particularly toxic to algae. Galvanized steel can be a cheaper alternative. For maximum effect, 2-4 inches of metal will be visible on your roof

Where Can I Find Qualified Roofers Near Me?

At Four Seasons Kanga Roof, we love when our customers have a do-it-yourself spirit. We hope that the tips we’ve provided serve you well, and you feel satisfied with the improved looks of your roof.

But if you find yourself needing professional care, we’re here for you. We provide top-quality residential roof repair and roofing installation services at an affordable price. Our skilled team can offer additional support for your cleaning project or provide input should you decide to pursue roof replacement.

You care about the roof over your head. We care, too. Contact us to schedule your next roofing service.



Call our team today to learn more about current specials for your roof.