Cleaning a Metal Roof

By Amanda Lutz Updated May 2, 2024

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Metal roofs are popular because they’re durable, have a sleek appearance, and require little maintenance. Homeowners should still clean them now and again to remove buildups of dirt, debris, mold, and other particles that can lead to premature deterioration.

Our guide offers tips on how to clean a metal roof safely and effectively with products such as mild laundry detergent and mild dish soap. We’ll also help you decide whether to clean your roof as part of a do-it-yourself project or call a professional roof cleaning service. 

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Why Does a Metal Roof Need to be Cleaned?

Your metal roof is an investment that plays an important role in protecting your home. Metal roofs typically require less maintenance than other roof types, such as asphalt shingles, but they still need occasional cleaning.

Clearing your metal roof of dirt, leaves, and twigs immediately boosts your home’s curb appeal. Periodic cleaning also removes particles and pollutants that could degrade the paint or substrate of your roof’s metal panels. Your clean roof will improve your home’s appearance, extend its life span, and improve your home’s value.


Best Metal Roof Cleaning Tools

Metal roofing requires very specific cleaning tools. The material is durable, but the roof’s finish is susceptible to damage from sharp or abrasive objects. Gather the following tools and materials before getting started. 


Best Metal Roof Cleaning Products

Metal roofs typically feature sealants, coatings, or paint that protect them against the elements. The best metal roof cleaning products are gentle enough to avoid damaging these protective coatings. Consider the following cleaning products:

Plain Water

Once you’ve removed large debris from your roof, use a hose to spray plain water onto your roof to wash away dust, dirt, and other items that aren’t stuck to your roof’s surface. 

Detergents

Apply detergent solutions to your roof with a sponge or washcloth, and let them sit for five to 10 minutes. Do not let the solutions stay on long enough to dry on the roof’s surface.

The most common solution for cleaning metal roofs is a combination of dish soap, laundry detergent, or car washing soap mixed with water. You can use one of the following detergents mixed in a solution of 1/4 cup detergent to 1 gallon of water.

Solvents and Petroleum Solvents

Use solvents only in moderation on your roof to remove tough elements, such as grease, oil, paint, or tar. Test solvents before you use them.

Always follow the manufacturer’s instructions, and wear eye protection and gloves when using solvents. Keep your work area properly ventilated, and keep products away from open flames. 

Try these products in small amounts as needed for removing tough, non-water elements.


Special Metal Roof Cleaning Circumstances

As your roof ages and encounters lots of moisture, it may require a cleaning solution that’s stronger than a mild detergent solution. Read more about how to clean older roofs below.

Removing Mildew, Algae, or Mold on Metal Roofing

Homes in humid climates are more susceptible to mildew and mold growth on metal roofs. Cleaning stubborn mold and mildew requires a tougher cleaner and a full rinse. Take the following steps to remove mold and mildew. 

Removing Rust Stains on Metal Roofing

Early rust stains are often a result of stuck-on particles or grime. You can remove these rust-colored stains with a 5:1 solution of water and acid. Wear Neoprene or Nitrile gloves when working with acids. Begin by mixing 5 parts water with 1 part of one of the following acids.

Use a cloth to apply the solution to affected spots, and clean away rust stains with circular motions. Leave the solution on the surface for no more than five minutes, then rinse immediately. Repeat the process on all rust stains. If the rust doesn’t rinse away, call a professional.

The most common contributors to rusting include excess moisture, high salt content in the air, inadequate maintenance, and lack of protective coating. Routine maintenance is the most effective way to prevent the early rusting of your metal roof.


Metal Roof Cleaning Considerations to Remember

Cleaning your metal roof requires special considerations to stay safe and avoid damage to your roof. Follow the tips below for a successful cleaning project.


Our Recommendation

Cleaning your metal roof is a part of routine maintenance that can extend your roof’s life span and improve your property’s curb appeal. It’s a job you might be able to complete yourself, but only if you follow proper safety protocol. Consider hiring a professional roofer if you’re not sure about your abilities. Use gentle cleaning solutions and non-abrasive tools to keep your roof looking brand new for years to come. 


Cleaning a Metal Roof FAQ

What is the best thing to clean a metal roof with?

The best thing to clean a metal roof with is plain water. If grime persists, use a solution of mild detergent and water.

Is it OK to pressure wash a metal roof?

It is not OK to pressure wash a metal roof. The high pressure of a power washer can dent the metal, damage the roof’s protective coating, and drive the roof’s seams apart. Using a pressure washer may also void your roof’s warranty.

How do you remove mold and mildew from a metal roof?

You can remove mold and mildew from a metal roof with a solution of 1/3 cup of powdered laundry detergent, 1 quart of bleach, and 3 quarts of water. Make sure to rinse the area thoroughly after cleaning.

Does Wet & Forget work on metal roofs?

Wet & Forget cleaning product works well on metal roofs. However, make sure that the active ingredient, alkyl dimethyl benzyl ammonium chloride, is safe for your roof and won’t void your warranty.

When should I hire a professional to clean my metal roof?

You should hire a professional to clean your metal roof if you don’t think you can complete the job yourself. If you’re unable to safely climb a ladder, don’t have the right equipment, or feel uncomfortable working on a roof, call a professional.