How to Clean a Metal Roof
Give your roof a better look and more efficiency in protecting your house
Whether your metal roof is found on a commercial building, a residential building, or even a shed or other type of structure, it is essential to keep it clean and well-maintained. With proper metal roof maintenance, it can last for decades.
A clean metal roof will not only look better, but it will also be more effective at doing its job of protecting your home or business from the elements. Dirt, leaves, and other debris can accumulate on the roof and cause it to deteriorate over time. Likewise, a build-up of dirt and debris can also lead to a decrease in the roof's ability to reflect heat, which can increase your energy costs.
We'll go over what you'll need to clean your metal roof, a step-by-step guide to cleaning your metal roof, and how to prevent dirt and debris from accumulating on your metal roof below.
Why Does A Metal Roof Need To Be Cleaned?
Homeowners should clean a metal roof for two main reasons: to improve its appearance and to prevent damage. As we mentioned, a build-up of dirt and debris can make your metal roof look dull and can even lead to rust and other forms of corrosion. While a metal roof is designed to withstand the elements, it is not immune to damage from the build-up of dirt and debris.
#1: Cleaning Extends The Life Of A Metal Roof
The first benefit of cleaning a metal roof is that it will extend the roof's life. A metal roof may endure decades of weathering, but only if it is properly maintained. If left uncleaned, dirt and debris can eventually eat away at the roof's protective coating. Without the protective coating, moisture can lead to rust and other problems down the line. Metal roofs are particularly susceptible to dirt and grime if they are located near trees or other sources of debris.
#2: Get Rid Of The Elements Stuck On The Roof's Surface
Cleaning a metal roof will also get rid of any elements that may stick to the roof's surface. Maintaining a clean surface is important because these elements can eventually work their way into the metal and cause rust or other damage.
Common elements that should not be left on a metal roof include:
- Dirt
- Grit
- Bird droppings
- Tree Sap
- Pine needles
- Leaves
- Birds' Nests
- Rainwater
- Pollen
- Mold
- Rust
- Mildew
If left too long on a roof, these materials can cause severe damage, including rust, stains, and dents, which can lead to leaks.
#3: Maintains The Aesthetics Of A Metal Roof
A well-maintained and clean roof should help improve the curb appeal of your home or business. Conversely, a dirty or stained roof can make a building look old and neglected. By regularly cleaning your roof, you can ensure that it looks its best and maintains its value.
How To Clean A Painted Metal Roof
Cleaning a painted metal roof will require some care and finesse to avoid damaging the paint or finish on your roof. You'll want to avoid using harsh chemicals, stiff brushes, and abrasive scrubbers when cleaning a painted roof. Instead, opt for a soft bristle brush or sponge and a cleaner that is safe for use on painted surfaces.
The method we recommend is a gentle approach that might not be enough for tough stains. If you're worried about getting the job done safely or efficiently, call a professional roof cleaning service to help.
Metal Roof Cleaning Products And Tools
To safely and effectively clean your painted metal roof, you will need plain water, a gentle detergent, a ladder, a cleaning brush, and something to help you dry off the roof once you're done.
Plain Water
The first step in cleaning your painted metal roof is to simply rinse it off with plain water. Rinsing will help to remove any loose dirt, debris, or other elements that may stick to the roof. A high-pressure washer is probably the wrong tool for this step, as it could damage the paint on your roof. Later, we'll discuss when to use a pressure washer, as well as a few pros and cons to consider.
Metal Roof Cleaning Mix
After you have rinsed off your roof with plain water, you will need to create a metal roof cleaning mix. You can make this mix by combining a variety of ingredients, but any gentle detergent solution mixed with water should do the trick. Some examples of gentle cleaners include:
- Trisodium phosphate
- Mild laundry detergent such as powdered Tide
- Mild Dish soap
- Car cleaner
Once you have mixed one of these products with a few gallons of cold water, you will need to apply the cleaning solution to your roof with a garden sprayer. First, be sure to coat the entire surface of the roof evenly. Once it's been evenly spread, leave it for about 10 minutes to let the chemicals work for you.
Metal Roof Cleaning Brush
After you have applied the metal roof cleaning mix, it's time to start scrubbing. For this step, you will need a soft-bristled brush or sponge. We don't recommend using a wire brush in this step as it could damage the paint on your roof. Instead, opt for a natural fiber brush or a synthetic bristle brush. Start by scrubbing the entire surface of your roof in a circular motion. Be sure to pay special attention to any areas that seem particularly dirty or stained.
Solvent
If you're dealing with tough stains, you might need to use a solvent-based cleaner. These products are designed to remove tougher materials, such as tree sap or bird droppings. However, they can also be harsh on painted surfaces. As such, you should only use them as a last resort and always follow the manufacturer's instructions to avoid damaging your roof. Before applying to your roof, you can check the ingredients to determine if they contain any paint removers such as methylene chloride, which is also highly toxic.
Common solvents you might consider include:
- Muriatic acid
- Vinegar
- Rubbing alcohol
- Mineral spirits
These solvents can be dangerous, so be sure you know what you’re doing before opting to use this on your roof. In most cases, you’ll need to heavily dilute your solvent before applying it, as well as collect any runoff for proper disposal.
Cloth Or Sponge
Once you have scrubbed the entire surface of your roof, you will need to rinse it off with plain water. You can use a garden hose or a bucket of water for this step and a cloth or sponge to remove the remaining detergent or solvent. Be sure to rinse the roof thoroughly to remove any residue from the cleaning solution.
Special Metal Roof Cleaning Circumstances
Sometimes metal roofs gather more debris than simple piles of leaves and dirt. If your roof falls into any of the categories below, you can try a DIY method of cleaning, or you may want to consider hiring a professional cleaner to ensure your roof gets clean without causing damage to the paint.
Removing Mildew, Algae, Or Mold On Metal Roofing
If you live in an area with a lot of humidity, your roof is at risk of developing mildew, algae, or mold. These can be tough to remove and may require special cleaners or solvents. For mildew and algae, the best option is to mix one part bleach with three parts water and apply it to the affected areas with a sponge or cloth. Let it sit for about 15 minutes before rinsing it off with plain water.
If you're dealing with mold, you will likely need to use a special mold-killing solution. These can be found at most hardware stores. Be sure to follow the manufacturer's instructions carefully, as some of these solutions can be harsh.
Removing Rust Stains On Metal Roofing
If your metal roof is rusty, you will need to take particular care when cleaning it. Rust can be tricky to remove and may require special cleaners or solvents. For minor rust stains, you can try using a mixture of vinegar and water. Apply this mixture to the affected areas with a sponge or cloth and let it sit for about 15 minutes before rinsing it off with plain water. It's important that you don't aggressively scrub the rust as this could scratch the paint on your roof.
For more significant rust stains, you might need to use a more powerful solution, such as oxalic acid. You can find this at most hardware stores. We recommend applying this mixture sparingly with nothing more abrasive than a toothbrush, so leave the steel wool under the sink. If any rust remains after rinsing the area, you can gently scrub with a wire brush. Be sure to follow the manufacturer's instructions and wear goggles and gloves when working with chemicals.
Pressure Washing A Metal Roof
If you have a large metal roof, you may want to consider pressure washing it. Pressure washing is a more powerful cleaning method that can remove tougher stains and debris. However, it's important that you use the right type of power washer. We recommend using an electric pressure washer with a psi of no more than 1200 as anything higher can damage the paint and finish on your roof.
If you're going to power wash your metal roof, be sure to start from the top and work your way down at a 45-degree angle to the roof surface. This method will prevent any water or debris from getting trapped under the panels. You should also avoid using too much pressure or heat as this could damage the roof.
If you've never used a pressure washer, have never worked on a roof, or are doing this project alone, we do not recommend cleaning with a pressure washer. These machines, while powerful, can quickly become dangerous if dropped, misdirected, or misused. We always recommend having someone else help you with this project, even if they're just holding the ladder.
Take Safety Precautions
Cleaning a metal surface can be dangerous. It's easy to slip and fall on a slick roof or ladder, and gloves, goggles, and proper footwear can be the difference between a typical project and a trip to the hospital. Here are some things to keep in mind:
- Wear protective clothing, including gloves, goggles, and a dust mask.
- Never clean metal panels in direct sunlight as the chemicals can be more potent.
- Be sure to have someone else hold the ladder for you.
- Start from the top of the roof and work your way down.
- Use mild detergent and cleaners whenever possible.
- Have a plan for collecting runoff from harsh chemicals
Cleaning a metal roof doesn't have to be difficult and taking these precautions can help you avoid a serious accident. With the proper cleaners and a little elbow grease, you can get your roof looking new in no time. Just be sure to take safety precautions and use mild solutions whenever possible. If you're unsure about anything, it's always best to consult a professional.
Have Your Metal Roof Professionally Cleaned
If you're not comfortable cleaning your metal roof yourself or if you have a large project, you may want to consider hiring a professional. Many companies specialize in metal roof cleaning, and they have the experience and equipment to get the job done quickly and safely.
Hiring a professional is always the best option if you're not comfortable cleaning your roof yourself. Just be sure to do your research and hire a reputable company. As always, if you discover any damage in the cleaning process, our team is here to help. Schedule a consultation today and we'll help you get your roof back in tip-top shape.
