How to Clean a Metal Roof Like a Pro

In this post, we show homeowners how to clean their metal roofs step by step. Keep reading to learn more!
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Reviewed by JC Sanjuan — General and roofing contractor with over a decade of experience in residential and commercial construction. He specializes in project management, quality workmanship, client satisfaction, and solving roofing challenges.

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If you have a metal roof, keeping it clean is key. It’s not just about looks – a clean roof lasts longer too. Over time, all sorts of stuff like dirt, leaves, and even mold can build up. This article is all about how to clean your metal roof the right way.

We’ll talk about the best tools to use, the right way to do it, and what you should avoid so you don’t damage your roof. We’ll also touch on when it might be a good idea to call in the pros. Stick with us, and we’ll show you how to keep your metal roof looking great and in good shape for years.

Why Clean Your Metal Roof?

Person cleaning metal roof with pressure wash
Credit: The Roof Dudes

Cleaning your metal roof is a maintenance task that pays off in more ways than one. Here’s why you should make it a priority:

1. Extends Roof Lifespan

A clean metal roof lasts longer. When dirt, debris, and algae accumulate, they can lead to corrosion and damage. Regular cleaning helps prevent these issues, ensuring your roof’s longevity.

2. Energy Efficiency

A clean roof reflects sunlight better than a dirty one. This means your property stays cooler, reducing the strain on your cooling system during hot Florida summers. It can lead to energy savings in the long run.

3. Curb Appeal

Your roof is a prominent part of your property’s exterior. A clean, well-maintained roof enhances your curb appeal. Whether you’re a homeowner or a business owner, a tidy roof makes a positive impression.

4. Prevents Leaks

Debris and algae can clog gutters and drainage systems, leading to water pooling on your roof. Over time, this can result in leaks and water damage. Regular cleaning prevents these issues.

5. Preserves Property Value

A well-maintained metal roof adds value to your property. When it’s time to sell, potential buyers are more likely to be impressed by a clean, durable roof. According to Remodeling’s 2019 Cost vs. Value Report, the average American homeowner spends $22,636 on a new asphalt shingle roof of midrange quality. That new roof will increase the home’s value by $15,427, on average. That works out to 68 percent of the investment.

Materials and Safety Precautions

How to stay safe when washing metal roofs
Credit: SolarPower World Online

Before you begin cleaning your metal roof, it’s important to gather the right materials and take necessary safety precautions. Here’s what you’ll need and some safety tips to keep in mind:

Materials Needed

  1. Safety Gear: Invest in safety equipment such as a sturdy ladder, non-slip shoes, and a safety harness if your roof has a steep pitch.
  2. Cleaning Solution:  You can either purchase a commercial roof cleaner or make a DIY solution using water and mild detergent. (Keep reading below)
  3.  Soft Bristle Brush: Opt for a soft-bristle brush or a broom with soft bristles to avoid damaging the metal surface.
  4. Hose or Pressure Washer: Depending on your preference, you can use a hose with a spray nozzle for manual cleaning or a pressure washer for a more powerful clean.
  5. Buckets and Cleaning Cloths: Have a few buckets for mixing solutions and cleaning cloths for wiping down the roof after cleaning.

Safety Precautions

  1. Use Proper Safety Equipment: Always wear appropriate safety gear, including a hard hat, gloves, and safety glasses. Make sure your ladder is stable and secure.
  2. Check the Weather: Avoid cleaning your roof during rainy or windy conditions. A wet roof can be slippery, making it dangerous to work on.
  3. Beware of Electrical Hazards: If you’re using a pressure washer, be cautious of power lines and electrical outlets. Keep the equipment away from these hazards.
  4. Avoid Walking on the Roof: While cleaning, try to stay on the ladder or use a roof anchor system if necessary. Walking directly on the roof can damage the metal panels.
  5. Work with a Partner: It’s safer to have someone else present when working on your roof. They can assist in case of an emergency.

Now that you have the right materials and safety precautions in place, you’re ready to prepare for the actual cleaning process. In the next section, we’ll discuss how to get your metal roof ready for cleaning.

Preparation on How to Clean a Metal Roof

Before you start cleaning your metal roof, it’s important to prepare the area and the roof itself. Proper preparation will help you be safe and make the process easier. Here’s what you need to do:

1. Clear the Area

Remove any obstacles or objects near the base of your roof, such as furniture, potted plants, or equipment. This creates a safe working space and prevents any damage from falling debris.

2. Protect Plants and Landscaping

Cover nearby plants and landscaping with plastic sheets or tarps to shield them from the cleaning solution and water runoff. Metal roof cleaning solutions can be harmful to plants.

3. Secure Ladders

Check that your ladder is stable and securely positioned against the roof. It’s best to have a reliable and safe means of accessing the roof.

4. Check Roof Condition

Before you start cleaning, inspect your metal roof for any visible damage, loose panels, or areas that may require repair. Address any issues before proceeding with cleaning.

5. Follow Product Instructions

If you’re using a commercial cleaning solution, read and follow the manufacturer’s instructions carefully. This help you use the product correctly and safely.

Cleaning Methods

When it comes to cleaning your metal roof, you have a few different methods to choose from. Each method has its advantages and considerations. Let’s explore them:

A. Manual Cleaning:

What You’ll Need: Soft bristle brush, cleaning solution, hose. Here are the steps:

  • Mix the cleaning solution as per the instructions.
  • Start from the top of the roof and work your way down.
  • Dip the brush in the cleaning solution and scrub gently in a circular motion to remove dirt and debris.
  • Rinse with a hose, ensuring you remove all cleaning residue.
  • Continue until the entire roof is clean.

B. Pressure Washing:

What You’ll Need: Pressure washer, appropriate nozzle, cleaning solution. Here are the steps:

  • Choose the right nozzle for your pressure washer (a wide-angle or fan nozzle is usually best).
  • Apply the cleaning solution to the roof surface.
  • Start at the top and work your way down, maintaining a safe distance to prevent damage.
  • Use a gentle, even spray pattern to remove dirt and grime.
  • Rinse thoroughly with water to remove any residue.

C. Soft Washing:

What You’ll Need: Soft washing system, cleaning solution. Here are the steps:

  • Soft washing uses low-pressure water combined with a specialized cleaning solution.
  • Apply the cleaning solution evenly across the roof’s surface.
  • Let it sit for the recommended time to allow it to break down dirt and algae.
  • Rinse the roof thoroughly with water, using low pressure.

D. Chemical Cleaning:

What You’ll Need: Specialized chemical cleaner, and safety gear. Here are the steps:

  • Chemical cleaning involves applying a specialized cleaner that reacts with algae and stains.
  • Follow the manufacturer’s instructions for mixing and applying the cleaner.
  • Allow the chemical to sit for the recommended time.
  • Rinse the roof thoroughly with water to remove the cleaning residue.

The cleaning method you choose depends on your comfort level, available equipment, and the level of cleaning required. Always prioritize safety and follow the manufacturer’s guidelines for any cleaning products you use.

Removing Stubborn Stains

If your metal roof has stubborn stains, don’t worry; there are effective ways to tackle them. Here’s how to deal with common stains like algae, rust, and more:

Algae Stains

Can Moss grow on Metal Roofs | ROTban
Credit: ROTban / rotban.ca

What You’ll Need: Algae-resistant roof cleaner, soft bristle brush.

  • Apply the algae-resistant cleaner to the stained areas as directed.
  • Allow it to sit for the recommended time to break down the algae.
  • Gently scrub the stained areas with a soft bristle brush.
  • Rinse the roof thoroughly with water to remove the residue.

Rust Stains

metal-roof-rusting
Credit: RPS Metal Roofing & Siding

What You’ll Need: Rust remover, soft bristle brush.

  • Apply the rust remover to the rust stains as directed.
  • Allow it to sit for the recommended time to dissolve the rust.
  • Carefully scrub the stained areas with a soft bristle brush.
  • Rinse the roof thoroughly to remove any remaining rust remover.

Tree Sap or Bird Droppings

the-real-safety-hand-health-risks-of-bird-droppings
Credit: Birdbarrier.com

What You’ll Need: Warm soapy water, soft cloth.

  • Soak the affected area with warm, soapy water.
  • Gently rub the sap or droppings with a soft cloth until they come off.
  • Rinse the area thoroughly to remove any soap residue.

Mold and Mildew

metal-roof-mildew-mold
Credit: World Glass Window Cleaning Seattle

What You’ll Need: Mold and mildew cleaner, soft bristle brush.

  • Apply the mold and mildew cleaner to the affected areas as directed.
  • Let it sit for the recommended time to kill and loosen the mold or mildew.
  • Gently scrub the stained areas with a soft bristle brush.
  • Rinse the roof thoroughly to remove any remaining cleaner.

Top Metal Roof Cleaning Products

  • Plain Water: For basic cleaning, using a hose with plain water can often remove dirt, dust, and light debris. Make sure you use enough water to thoroughly clean the surface.
  • Detergents: Mild detergents like laundry detergent, car washing soap, mild dish soap, or commercial/industrial detergents are safe and effective for most metal roofs. Here’s how to use them:
  • Mix: 1/4 cup detergent (5% detergent solution) per gallon of water.
  • Apply the solution with a sponge or washcloth.
  • Let it sit for 5 to 10 minutes.
  • Rinse the surface thoroughly with plain water.
  • Solvents & Petroleum Solvents: Solvents are useful for removing tougher substances like oil, paint, grease, tar, and graffiti. However, use them only on specific areas, not the entire roof. Follow the product label instructions and wear protective gear. Common solvents include:
  • Rubbing alcohol (Isopropyl)
  • Mineral spirits
  • VM&P Naphtha
  • Remember to handle these solvents with care, as they can be toxic and flammable.

Special Metal Roof Cleaning Circumstances

Removing Mildew, Algae, or Mold:

  • Mix 1/3 cup powdered laundry detergent + 1-quart bleach (5% solution) + 3 quarts water.
  • Apply the cleanser to affected areas using a soft brush or rag.
  • Gently scrub until the mildew or mold is gone.
  • Rinse the surface thoroughly with plain water.

Removing Rust Stains:

  • For mild rust stains, remove the particles causing the stains.
  • Use a mild abrasive cleaner (soft scrub) on a non-abrasive pad.
  • Apply light pressure and work on the stain until it disappears.
  • Rinse thoroughly.

For severe rust stains, follow these steps:

  • Remove the particles causing the rust stains.
  • Mix: 5 parts water + 1 part diluted hydrochloric acid OR citric acid OR muriatic acid OR oxalic acid OR vinegar.
  • Apply the mixture with a rag to the affected spots using circular wiping motions.
  • Rinse immediately after the rust stain clears.
  • Do not leave the solution on the surface for more than 5 minutes, and do not let it dry.

If rust stains persist, consult your manufacturer or contractor for further assistance as it may indicate a more significant issue.


Maintenance Tips

Keeping your metal roof clean and well-maintained doesn’t end with the cleaning process. Here are some helpful maintenance tips to guarantee your roof stays in excellent shape year-round:

  • Regular Inspections: Periodically inspect your metal roof for any signs of damage, loose panels, or areas in need of repair. Address any issues promptly to prevent further damage.
  • Gutter Maintenance: Clean your gutters regularly to prevent debris buildup. Clogged gutters can lead to water pooling on your roof and potential leaks.
  • Trim Overhanging Branches: If you have trees near your roof, trim overhanging branches to prevent leaves and debris from accumulating on the roof’s surface.
  • Check Sealant and Flashing: Inspect the sealant and flashing around roof penetrations like vents and chimneys. Check if they are in good condition to prevent leaks.
  • Yearly Cleaning: Consider an annual or bi-annual roof cleaning to remove dirt, algae, and other contaminants. Regular cleaning helps maintain your roof’s appearance and durability.
  • Avoid Walking on the Roof: Minimize foot traffic on your metal roof to prevent potential damage to the panels. Only walk on the roof when necessary and with proper precautions.
  • Professional Inspections: Periodically, have your roof inspected by a professional roofing contractor. They can identify issues early and provide expert guidance on maintenance.
  • Keep Records: Maintain a record of your roof’s maintenance and cleaning schedule. This helps you stay organized so you don’t miss essential tasks.

When to Have Your Roof Cleaned by a Professional

While DIY roof cleaning is a viable option, there are situations where hiring a professional roofing contractor for the job is the better choice. Here’s when you should consider professional roof cleaning:

1. Safety Concerns
If your roof has a steep pitch or is difficult to access safely, it’s best to leave the cleaning to professionals who have the right equipment and training.

2. Lack of Experience
If you’re not comfortable working at heights or lack experience with roof cleaning, hiring a professional might be best so the job is done correctly.

3. Extensive Stains or Damage
For roofs with severe staining, extensive algae growth, or damage, professionals have the expertise and tools to address these issues effectively.

4. Warranty Considerations
If your metal roof is under warranty, it’s important to check the manufacturer’s requirements. Some warranties may require professional cleaning to remain valid.

5. Time and Convenience
Hiring a professional saves you time and effort. They can complete the job efficiently, allowing you to focus on other priorities.

6. Quality Results
Professionals have access to commercial-grade cleaning products and equipment, ensuring a thorough and high-quality cleaning job.

7. Preventing Damage
Incorrect DIY cleaning methods can damage your roof. Professionals have the knowledge to clean your roof without causing harm.

Before hiring a professional, be sure to research local roofing contractors, check their credentials, and request quotes from multiple sources to ensure you get the best service and value.

Wrapping Up

Maintaining a clean metal roof is a key part of preserving your home or business’s appearance and structural integrity. Whether you’re tackling the task yourself or considering professional assistance, here’s a quick recap of what you’ve learned:

  • Cleaning your metal roof extends its lifespan, enhances energy efficiency, and boosts curb appeal.
  • Prioritize safety with the right equipment and precautions.
  • Preparation makes a smooth and safe cleaning process.
  • Choose a cleaning method that suits your needs, whether it’s manual cleaning, pressure washing, soft washing, or chemical cleaning.
  • Stubborn stains like algae, rust, and more can be effectively removed with the right techniques and products.
  • Regular maintenance, including inspections and gutter cleaning, keeps your roof in top condition.
  • Consider hiring a professional when safety, lack of experience, extensive damage, or warranty considerations are factors.

By following these guidelines and keeping your metal roof clean and well-maintained, you’ll enjoy the benefits of a roof that not only looks great but also protects your property for years to come.

If you have any more questions or need further assistance with your roof cleaning endeavors, feel free to reach out to us. Thank you for taking the time to learn how to clean a metal roof effectively.


Frequently Asked Questions

1. Can I clean my metal roof myself, or should I hire a professional?

You can clean your metal roof yourself if you have the necessary tools and feel comfortable working at heights. However, hiring a professional may be safer and more efficient, especially for steep roofs or extensive staining.

2. What’s the best time of year to clean a metal roof in Florida?

Ideally, choose a dry, mild day for roof cleaning. Avoid rainy or extremely hot and sunny days, as they can affect the cleaning process.

3. Are there any specific cleaning products I should use for a metal roof?

You can use a commercial metal roof cleaner or make a DIY solution with water and mild detergent. Be sure to follow the manufacturer’s instructions for any cleaning products you use.

4. How often should I clean my metal roof?

Regular cleaning every 1-2 years is generally recommended to maintain your roof’s appearance and durability. However, the frequency may vary depending on your location and local climate conditions.

5. Can I walk on a metal roof during cleaning?

While it’s possible to walk on a metal roof, it’s best to minimize foot traffic to prevent potential damage. Use a ladder or roof anchor system when necessary and take proper precautions.

6. Are there any precautions I should take when cleaning near plants or landscaping?

Yes, cover nearby plants and landscaping with plastic sheets or tarps to protect them from cleaning solutions and water runoff, as some cleaning solutions may be harmful to plants.

7. Will cleaning my metal roof affect its warranty?

Check your metal roof’s warranty guidelines. Some warranties may require professional cleaning to remain valid, so be sure to follow the manufacturer’s recommendations.

8. How can I prevent future stains on my metal roof after cleaning?

Regular inspections and maintenance can help prevent future stains. Address issues like overhanging branches and clogged gutters promptly to minimize debris accumulation.

9. Can I use a pressure washer to clean my metal roof?

Yes, a pressure washer can be used for metal roof cleaning, but it should be used with caution to avoid damage. Choose the right nozzle and maintain a safe distance from the roof surface.

10. Is it necessary to rinse the roof thoroughly after cleaning?

Yes, rinsing the roof after cleaning is crucial to remove any cleaning residue and prevent damage to the metal surface.


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