2024’s Best Roof Cleaners for Mold, Mildew, and More

Bring your home’s roof back to its original glory by removing dark streaks, moss, and other roof-hitchhiking debris. These cleaners will help.

Best Overall

Bottle of Wet and Forget moss mold mildew & algae stain remover

Wet and Forget Moss, Mold and Mildew Stain Remover

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RUNNER-UP

Bottle of 30 Seconds Ready to Use Outdoor Cleaner

30 Seconds Ready to Use Outdoor Cleaner

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BEST BANG FOR THE BUCK

Two bottles of Mold Armor E-Z House Wash

Mold Armor E-Z House Wash

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While most homeowners spend the majority of their time maintaining the ground-level features of their homes, a roof cleaner can help maintain the outside appeal. It’s not until dirty, dark streaks and patches of moss show up that they realize their neglect is affecting their roof.

We recommend Wet and Forget as our top pick for its versatility, large coverage area, and ease of use. To clean your roof, all you need to do is block out some time, arm yourself with the best roof cleaner, and get to work. In conjunction with a little spraying and scrubbing, these special formulas will have your roof looking fresh and renewed in no time. We evaluated the best roof cleaners and even hands-on tested one of them so you’ll be able to cut through the dirt, grime, and sludge, revealing your roof’s true colors.

  1. BEST OVERALL: Wet and Forget Moss, Mold and Mildew Stain Remover
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  2. RUNNER-UP: 30 Seconds Ready to Use Outdoor Cleaner 
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  3. BEST BANG FOR THE BUCK: Mold Armor E-Z House Wash
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  4. BEST CHEMICAL: Spray & Forget Revolutionary Roof Cleaner Concentrate
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  5. BEST ECO-FRIENDLY: Simple Green Industrial Cleaner & Degreaser
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  6. BEST PRESSURE: Simple Green Oxy Solve Total Outdoor Cleaner
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  7. BEST FOR MOLD REMOVAL: Rust-Oleum Jomax Spray Once Roof Cleaner
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  8. BEST FOR EXTERIOR MILDEW: Star Brite Mildew Stain Remover
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Man standing on a roof, cleaning it with a sprayer
Photo: amazon.com

How We Chose the Best Roof Cleaners

There are multiple factors to consider when shopping for the appropriate roof cleaner, from the surface of the roof itself to the specific dirt issues that homeowners are faced with. Our list of recommended products covers the wide array of cleaners available for mold, moss, and mildew to provide the best suggestions for each scenario. 

In our research we found that shoppers have different expectations of the effort involved in maintaining a roof. Some shoppers prefer a simple one-time spray solution that requires no scrubbing or roof washing to remove light stains, while others with stubborn stains on their roof are looking for heavy-duty chemicals that can make short work of the problem. Our top picks meet the needs of most shoppers to provide a clean roof.

One of the most important factors to keep in mind is the chemicals used in each product. Heavy-duty solutions tend to use bleach and other harsh chemicals, which are not always what shoppers are looking for. We made sure to provide a wide range of options, from highly effective—but perhaps more harmful—to the most environmentally friendly solutions on the market.

Our Top Picks

Before calling in a roof cleaning service, check out the products listed below. They are some of the best roof cleaners available for removing ugly stains, algae, and dirt. You’ll find budget-friendly options, products with environmentally safe formulas, and heavy-duty formulas for tough stains. Compare these roof cleaning products to ensure you choose the best option for your needs.

Best Overall

Wet and Forget Moss, Mold and Mildew Stain Remover

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Product Specs

  • Ingredient type: Chemical-based 
  • Compatible roof surfaces: Wood, vinyl, clay, metal, concrete, canvas, PVC, aluminum, and more
  • Coverage area: Up to 1,125 square feet 

Pros

  • Half-gallon bottle of cleaner can cover up to 1,125 square feet of space; creates 3 gallons of cleaner 
  • Simply apply and allow the product to take effect; suitable for those who prefer a set-and-forget application 
  • Suitable for a wide variety of outdoor surfaces and materials for peak versatility
  • Made with a bleach-free, non-caustic, and non-acidic formula 

Cons

  • Should not be applied near wildlife; chemical composition is not safe for plants

The quicker you can clean your roof and move on to enjoying your free time, the better. The Wet and Forget Moss, Mold, and Mildew and Algae Stain Remover offers a one-step process that will remove roof buildup, reactivating and washing contaminants from the surface each time it rains. Its bleach-free, non-caustic, non-acidic, chemical-based formula means you can use it on your roof, as well as almost any other outdoor surface.

After you spray your roof, as the name implies, you can let Wet and Forget do its thing. You’ll only need to reapply if you see new growth or black streaks and stains reappearing. This concentrated roof treatment comes in a half-gallon bottle that you can dilute to make up to 3 gallons of cleaner. Depending on the strength you mix, and how porous your roof material is, you can cover anywhere between 375- and 1,125-square-foot spaces with one bottle of this roof stain remover.

What our tester says: Tom Scalisi, a Bob Vila writer and product tester, notes in the Best Deck Cleaners that he tested Wet & Forget on a concrete foundation. “I waited until a bright morning with no rain forecast and sprayed the foundation thoroughly, following the instructions to let the solution soak in for up to 5 hours. Later, I returned and found the previously mold-darkened areas to look light and powdery. I used a stiff dry brush to remove the powder, and the concrete blocks beneath looked clean, with no dark or stained areas.” 

Get the Wet and Forget roof cleaner at Amazon or Ace Hardware (1 gallon).

Runner-up

30 Seconds Ready to Use Outdoor Cleaner

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Product Specs

  • Ingredient type: Eco-friendly 
  • Compatible roof surfaces: Masonry, metal, slate, and more 
  • Coverage area: Up to 600 square feet

Pros

  • Ready-to-use sprayer attachment is convenient for the application process 
  • Biodegradable formula is safe to use around children, pets, and wildlife 
  • Removes dirt, grime, algae, mold, mildew, and discoloration for better curb appeal 
  • 1.3-gallon container can cover 200- to 600-square-foot spaces

Cons

  • Some users have reported a strong smell is emitted during the application process 
  • The packaging of the sprayer may leak before arrival or when being stored 

Eco-friendly products do their jobs while providing peace of mind. Made with a biodegradable and eco-friendly composition, 30 Seconds removes discoloration, dirt, grime, mold, mildew, and algae and comes with a ready-to-use sprayer attachment. 

The contents of the package can cover 200 square feet when used on porous surfaces and up to 600 square feet on nonporous surfaces. This fast-acting biodegradable cleaner can be used on rooftops as well as brick, masonry, decks, composite, siding, gutters, painted or stained surfaces, and more. 

Get the 30 Seconds roof cleaner at Amazon or Walmart.

Best Bang For The Buck

Mold Armor E-Z House Wash

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Product Specs

  • Ingredient type: Chemical-based 
  • Compatible roof surfaces: Vinyl, brick, stucco, aluminum, concrete and more
  • Coverage area: 4,500 square feet 

Pros

  • Begins killing mold and mildew in just 10 minutes for either deep or soft wash roof cleaning
  • Wide surface area coverage compared with other roof cleaners; 1 jug covers up to 4,500-square-foot spaces 
  • Ready-to-use hose attachment provides excellent ease of application 

Cons

  • Some users have reported that this option has poor or finicky packaging 

If you’re looking for a heavy-duty roof wash with a straightforward application process at a value-minded price, it’s hard to beat this two-pack of Mold Armor’s E-Z House Wash. This product comes in two half-gallon bottles of cleaner, each with a hose attachment for extremely easy application.

The Mold Armor E-Z House Wash hose attachment will reach second-floor roofs without issue, and it starts killing mold and mildew within 10 minutes of application. There’s no follow-up scrubbing necessary either; simply apply, allow it to work for 10 minutes, and rinse it off to reveal a clean surface.

Get the Mold Armor roof cleaner at Amazon or The Home Depot (single).

Best Chemical

Spray & Forget Revolutionary Roof Cleaner Concentrate

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Product Specs

  • Ingredient type: Chemical-based 
  • Compatible roof surfaces: Asphalt, wood, slate, clay, and tile 
  • Coverage area: Up to 2,000 square feet 

Pros

  • 1 gallon of cleaner concentrate makes 10 gallons of roof cleaner; covers 1,000 to 2,000 square feet 
  • Reacts every time it rains; lasts for 3 to 6 months before it requires reapplication
  • Versatile product; suitable for a variety of roofing materials 

Cons

  • May require some elbow grease for best results

Spray & Forget Revolutionary Roof Cleaner Concentrate is worth checking out if you’re looking for a one-step cleaner specifically formulated for your roof. This 1-gallon jug of concentrate mixes with water to create up to 10 gallons of cleaner, offering a maximum coverage of 2,000 square feet.

The Revolutionary Roof Cleaner continues to clean your roof after application, eliminating the need to scrub or reapply. The roof wash formula reactivates each time it rains, providing follow-up cleanings for up to 3 to 6 months at a time. It’s safe for use on asphalt, wood, slate, clay, and tile shingles, though you should avoid using it on rubber or vinyl. 

Get the Spray & Forget roof cleaner at Amazon or The Home Depot.

Best Eco-friendly

Simple Green Industrial Cleaner & Degreaser

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Product Specs

  • Ingredient type: Eco-friendly
  • Compatible roof surfaces: Cement, concrete, enamel, metal, and plastic
  • Coverage area: Customizable

Pros

  • Nontoxic formula is biodegradable and safe to use around children, pets, and wildlife 
  • Can be used indoors and outdoors; it cuts through oil, grease, black streaks, stains, dirt, and grime with ease 
  • Versatile application process; can be used with a roller, sponger, sprayer, or pressure washer 

Cons

  • A couple of applications may be required to dial in the dilution needed for effective cleaning 

When it comes to an eco-friendly roof cleaner, consider going with the original in the environmentally conscious business. Simple Green’s cleaner and degreaser is a nontoxic alternative to chemical-heavy products. While it’s nontoxic and biodegradable, this roof wash is powerful enough to cut through oil and grease, so the dirt and grime on your roof shouldn’t be an issue.

This 5-gallon bottle is a concentrate, so you’ll be able to mix it with water or use it at full-strength to cut through tougher stains. You can apply it with a roller, sponger, or sprayer, but its eco-friendly formula means you can use it for roof pressure-washing without worrying about overspray. This option should be ideal for most power- washing companies and manufacturers. 

Get the Simple Green industrial roof cleaner at Amazon or DK Hardware.

Best Pressure

Simple Green Oxy Solve Total Outdoor Cleaner

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Product Specs

  • Ingredient type: Eco-friendly 
  • Compatible roof surfaces: Wood, plastic, vinyl, metal, and more 
  • Coverage area: 6,300 square feet 

Pros

  • Can be added straight into the tank of a pressure washer
  • Removes dirt, grime, mold, mildew, algae, and stains for all-around cleaning power 
  • Eco-friendly formula can be used around wildlife, children, and pets 
  • 1 gallon of the concentrate can make over 21 gallons of roof cleaner; suitable for large homes 

Cons

  • Tougher stains may require scrubbing or deep-cleaning; not as abrasive as comparable options 

Pressure-washing with harsh chemicals can cause a lot of unintended damage, as it’s hard to control your overspray. Simple Green Oxy Solve Total Outdoor Cleaner concentrate is worth checking into as it’s peroxide-based, so overspray won’t destroy your plant life or other surfaces. It lifts dirt, grime, and stains as well as mold, mildew, and algae, so it works well for the substances hanging out on your roof.

If you stretch out this concentrate to its most diluted but usable ratio, the 1-gallon jug can make 21 gallons of cleaner. Those who run the concentrate straight through a pressure washer will be able to cover up to 6,300 square feet.

Get the Simple Green Oxy Solve roof cleaner at Amazon, The Home Depot, or Walmart.

Best For Mold Removal

Rust-Oleum Jomax Spray Once Roof Cleaner

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Product Specs

  • Ingredient type: Eco-friendly 
  • Compatible roof surfaces: Wood, asphalt, concrete, brisk, and more 
  • Coverage area: 1,500 square feet 

Pros

  • Eco-friendly formula is safe to use around plants, children, and pets 
  • Requires no scrubbing for effective cleaning; removes moss, mildew, and algae from a roof
  • Prevents the regrowth of mold and mildew, limiting need for reapplication 

Cons

  • Deep stains and tough mildew may require some scrubbing to remove 

If you’re looking for a heavy-duty cleaner to remove stubborn molds and the stains they leave behind on your roof, Rust-Oleum’s Jomax Spray Once concentrate could be the product for you. The bleach-free formula uses quaternary ammonium salts and ethoxylated alcohols to kill mold while still being safe to use around your plants.

This 1-gallon jug of concentrate yields 5 mixed gallons, providing up to 1,500 square feet of roof-cleaning coverage. Simply apply it to your roof surface and let it dry. It works with natural weather conditions to clean mold and prevent regrowth, requiring very little effort on your part.

Get the Rust-Oleum roof cleaner at Amazon or DK Hardware.

Best For Exterior Mildew

Star Brite Mildew Stain Remover

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Product Specs

  • Ingredient type: Chemical-based 
  • Compatible roof surfaces: Vinyl, rubber, plastic, tile, and more
  • Coverage area: Unlisted 

Pros

  • Comes with a large amount of concentrate for small to large surface areas 
  • Can be used on a wide variety of surfaces including boats, RVs, and those that are painted or made of fiberglass
  • Sodium hypochlorite and tetrasodium EDTA break down mold and mildew to provide deep-cleaning power 

Cons

  • Some users have reported a strong bleach-like smell during application

If mildew calls your roof home, you need a product specially designed to kill it and remove its stains. Star Brite’s Mildew Stain Remover uses sodium hypochlorite and tetrasodium EDTA to break down these challenging films. It’s safe for use on a variety of materials, including rubber roofing and vinyl siding.

You can apply this concentrate at full strength or dilute it for lighter stains. The application requires spraying the roof surface and letting it break down the stain. Once the stain disappears, rinse the roof thoroughly. If the stain remains after the roof dries, another application of Star Brite should remove the rest of the mildew.

Get the Star Brite roof cleaner at Amazon (1 gallon) or Walmart.

Jump to Our Top Picks

What to Consider When Choosing a Roof Cleaner

This section will outline the most important considerations to keep in mind while you’re shopping for the best roof cleaner for your home. It covers aspects like the different types of roofing materials, how much coverage you’ll get, and how easy the products are to use.

Types of Roof Cleaners

Don’t rush out and set up the ladder quite yet. You first need to educate yourself on the different types of roof cleaners available. They all work a little differently, and some are much harsher on the environment than others. It’s important to do a little research before you choose the best roof cleaner for your needs.

Bleach-Based

For particularly stubborn stains and discolorations, beach-based cleaners might be the way to go. They’re so strong, in fact, that you don’t even need to scrub or rinse the roof down for them to work. Simply apply them to the roof and let them dry. The bleach will eat through the dirt and grime all on its own.

Here’s the thing about bleach-based chemicals, though: They’re extremely harsh. They can bother you if you breathe in their vapors, and your overspray (or runoff when it rains) can wreak havoc on your plants. These cleaners are so strong that you should try to keep your windows closed for a few days to avoid the fumes and odors.

Chemical-Based

Bleach isn’t the only chemical manufacturers use to restore your roof to its former glory. Some formulas feature ammonia, copper sulfate, and trisodium phosphate, all of which can do a great job of removing the stains, molds, and mosses that grow on roofs.

These formulas can be harsh on your plants as well, though usually to a lesser degree than bleach-based cleaners. They rarely require the user to scrub or apply a second application, and in most cases, there’s no need to keep your windows closed after application. They usually come in concentrates, so you’ll probably want to mix them with water unless you have a really stubborn stain.

Eco-Friendly 

If you’re looking for a safer, less environmentally detrimental approach to cleaning your roof, check out an eco-friendly cleaner. These formulas break up the dirt, algae, and mold on your roof without the inherent dangers of chemical and bleach compounds. 

Eco-friendly cleaners are safe for your kids, plants, and the wildlife that might roam through your property. While it’s entirely possible to have some type of allergic reaction to these products, they’re generally safe.

Eco-friendly cleaners tend to use oxygen to break down dirt and roof-loving molds and algae, so they work best with a bit of agitation. Since you’ll probably have to scrub most of your stains and discolorations away, having a long-handled brush on hand will be incredibly helpful. 

Pressure Cleaner

If you want to blast your roof clean, you can always set up a pressure washer and get to work. The pump inside your pressure washer boosts the amount of pressure with which the water comes out of the nozzle, knocking dirt and film clear off your roof shingles.

But pressure washers can also blast your roof shingles off, so take care when you’re spraying your roof.

To help increase your pressure washer’s effectiveness, there are lots of products available that you can mix into the water. If you don’t use a chemical, realize that water alone might not kill any residual moss and algae.

Raw Chlorine 

Raw chlorine, also known as sodium hydrochlorite, cleans a roof while killing mold and mildew spores. This compound is made to sanitize, removing bacteria while also cleaning up stains and grime. When diluting, it’s important to ensure that raw chlorine solutions never comprise more than 30 percent of the roof-cleaning solution, and they should be rinsed after use.

Roof Material

The first thing you need to consider is the materials that make up your roof. Keep in mind that you need to consider all the materials to ensure you’re using the right product.

Less-durable materials like vinyl and rubber membranes found on flat roofs or RVs are particularly susceptible to damage from harsh chemicals. These heavy-duty cleaners can wear the roofing components down faster than if you used an eco-friendly option.

Tougher materials, like asphalt, metal, or slate roofs, can take much stronger chemicals. You’ll be able to use bleach or chemical-based cleaners without worrying about what they’ll do to your roof’s finish. 

Dilution and Chemical Composition

The best roof cleaners break down into two options: eco-friendly and chemical. Eco-friendly options don’t contain harmful chemicals, so they’re safe to use on roofs above gardens and plants. The composition of chemical-based products, on the other hand, isn’t always so environmentally conscious.

Chemical-based cleaners often use chemicals like ammonia, copper sulfate, and trisodium phosphate. They can be harsh, but they’re extremely effective at removing the stains as well as the molds, algae, and mosses that cause them. Simply diluting them to the manufacturer’s recommended mixture does reduce some of the risk, so read the directions carefully.

Coverage

Not all roof cleaners can cover the same amount of square footage, so it’s important to understand how much roof a bottle or jug can handle. To do this, you have to know the size of your roof first: Simply multiply each section of your roof’s width by its height. Tally each of those sections. The number you get after you add up all the different planes is your square footage.

Some of the best roof cleaners come in concentrated formulas that you can dilute for maximum coverage. While their bottles might be small, they can often cover thousands of square feet of roof if you dilute them correctly.

User-Friendliness

Cleaning your roof isn’t all that entertaining or fun, so it should be made as painless as possible. Finding a user-friendly product can make all the difference.

A chemical that you can spray on your roof and leave to do its work is by far the easiest way to clean your roof. Other chemicals might require you to scrub the surface, which can be a challenge for high roofs. 

Also, consider the application. Spray bottles can be easy to use, but they can make covering a large area difficult, so they’re ideal for smaller roofs. Concentrate bottles that attach to the end of your hose make applying the chemical to larger roofs extremely easy, but you might not be able to reach high peaks from the ground. Whatever you choose, be sure to select a product that you can apply easily for your particular roof.

Effectiveness

Ultimately, how well the product works at removing stains, molds, algae, and discolorations is one of the most important factors to keep in mind. The more effective the product, the fewer coats you’ll have to apply, and the less often you’ll have to apply it.

Less-effective products don’t always kill the root cause of the discoloration, even if the stain disappears. If that root is still present, there’s a good chance that whatever caused the stain will come back, and you’ll have to apply your product more often to keep up with it.

Harsh chemicals are by far the most effective and often take just one application. Eco-friendly products might take follow-up applications or more frequent cleanings.

FAQs 

For those who have additional questions about choosing or using the best roof cleaner, this section contains answers to some of the most frequently asked questions.

Q. How often does the roof need to be cleaned?

Many of the best roof cleaners recommend cleaning your roof every 12 to 24 months to ensure your roof stays clean and free from growths. But whenever you notice discoloration, moss, mold, or mildew, it’s a good idea to give your roof a spray.

Q. Can awnings be cleaned with roof cleaners?

It depends on the cleaner. Many of the heaviest-duty cleaners will damage vinyl or fabric awnings, while some biodegradable or lighter-duty cleaners will work quite well. However, it’s important to always refer to the product label before use. 

Q. Can a single roof cleaner be used with and without dilution?

Most roof cleaners are available in concentrated forms, and you can mix them to whatever strength you’d like. If you’re planning to use yours at full strength, it’s a good idea to test it on a smaller space first.

Q. How can plants be protected when using a roof cleaner?

There are a few steps you can take to minimize your roof cleaner’s impact on your plants.

Cover your plants in tarps or plastic sheeting.
Use only as much chemical as you need to.
Ensure your gutters aren’t clogged so any chemical-laden rainwater can flow away from the eaves.
Water your plants heavily before, during, and after using your cleaner. Diluting the concentration of chemicals is the best way to lessen the risk of damage.

Q. Is special equipment required to clean my roof?

Basic safety items like safety glasses, a respirator, and gloves are certainly important. You can also wear long sleeves. Using a long-handled brush or roller, or a garden sprayer, can make applying your roof cleaner a little more straightforward.

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Tom Scalisi

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Tom Scalisi is a freelance writer, author, and blogger with a passion for building. Whether it’s a DIY project or an entire website, Tom loves creating something from the ground up, stepping back, and admiring a job well done.

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