Composite decking is a popular choice because it is incredibly durable and lasts a long time. It is less likely to warp, rot, or splinter than standard wooden decking, and it still has a great aesthetic. However, like all decking materials, it requires proper care if you want it to stay in good condition.
Homeowners must understand how to clean their composite decking properly to preserve it and prevent a buildup of mold and mildew. When excess moisture is present, mold and mildew can thrive and cause a lot of damage to your decking. This guide will tell you everything you need to know about cleaning your composite decking and help you find the best mold and mildew cleaners on the market right now.
Is Regular Cleaning Required for Composite Decking?
Yes, you should always clean your decking on a regular basis. While composite decking is resistant to rot, water damage, and warping, mold and mildew can settle on the surface of your deck quickly if it isn’t cleaned and dried off properly. Allowing these substances to sit on the surface for too long will cause discoloration and potentially lead to long-term damage.
Using a hose to spray down your decking around once a month will stop the buildup of everyday dirt and grime. However, it will not prevent mold and mildew. You need to use a specifically formulated composite decking cleaner once or twice a year to tackle mold and mildew.
Can You Pressure Wash Composite Decking?
Pressure washers can be used to clean composite decking, but you need to be careful with the power. As a general rule, you should avoid going higher than 1500 PSI, but this varies depending on the manufacturer. Check out our full in-depth guide on pressure washing your composite decking for more detailed information.
It is important that you do your research before using a pressure washer or you risk leaving score marks in the decking.
How do You Clean a Composite Deck with Composite Deck Cleaner?
Composite deck cleaners are specially formulated cleaning products designed to remove mold, mildew, and other dirt and grime from your decking. Before using any product on your decking, you should always check the manufacturer’s instructions carefully as the process may vary slightly. However, most composite decking cleaners are used in a similar way. Here’s how to clean your deck with a composite deck cleaner.
Clear The Area And Sweep Away Debris
Before you start washing your deck, clear the surrounding area of any furniture and move anything that may get in the way. Sweep away any leaves and debris from high traffic areas to avoid causing damage during cleaning.
Rinse The Deck With Warm Water
Use a hose to rinse your deck with warm water. This will remove all of the surface dirt and will help prevent mold from becoming an issue. Avoid using high-pressure water as this can damage composite surfaces. If there is a lot of buildup on your decking, you may need to use a pressure washer at the lowest setting to loosen stubborn dirt. Alternatively, you can use a soft-bristled brush to scrub away any difficult bits.
Once you have given it a good rinse, your deck is ready for the composite deck cleaner.
Apply Composite Deck Cleaner And Scrub The Deck
Before applying your cleaning solution, check the instructions on the back. Apply it as instructed and then scrub the decking. The manufacturer should recommend the type of brush to use but, in most cases, a soft-bristled brush is the best option because it prevents scratches on the surface of the decking.
Make sure that you are thorough when scrubbing and get into all of the small gaps. It is important to ensure all mold and mildew are cleaned away so it doesn’t come back as soon as moisture settles on the deck.
Rinse The Deck
When you are confident that you have scrubbed every area, it’s time to rinse. Use a hose to spray the deck with fresh water. This rinsing step is particularly important if because it will remove all of the cleaning product from the surface of your deck. If any cleaner remains, it could leave a residue or soak into the deck and cause damage.
Let It Dry Fully
Make sure that you rinse away all residue before allowing your deck to dry off naturally in the sun. If you need to, move your furniture back into place once everything has dried completely. You can then use a soft cloth to give your deck a final buffing and shining if desired. If you move furniture or plants back onto the deck before it is fully dry, you risk trapping moisture and damaging the surface of the decking.
Now you know how to clean your composite decking, let’s take a look at some of the best products you can use.
10 Best Composite Deck Cleaners for Mold and Mildew
1. DeckMAX E2 PVC Deck Color Restorer 
This DeckMAX deck cleaner is perfect for cleaning and refreshing your deck and giving it a new lease of life. It’s suitable for all types of composite materials, including wood-plastic composite and PVC. It is easy to use and works great on decking boards that have been affected by mold growth.
The formula is designed to not only clean your decking but also to restore the original color to oxidized surfaces. It can also reduce the appearance of scuffs and stains, making it the perfect option for old decking. On top of that, it also provides added UV protection to reduce weathering.
It is a completely plant-based cleaner that is eco-friendly and non-toxic, so if you are concerned about damaging the surrounding garden, you don’t need to worry. Application is very simple as there is no sanding or pre-stripping required, and it dries quickly too.
If you have old composite decking and you want to bring it back to life, this cleaning solution is ideal.
2. Wash Safe Industries Clear Spray and Clean Composite Deck Cleaner
This Wash Safe Industries deck cleaner is ideal for cleaning all types of decks, including wood-plastic composites. It provides an easy way to clean your deck without harming the surrounding environment or plants. It is specifically formulated to clean decking installed before 2010 (known as the first generation of decking) and it is suitable for use with all major brands. If your decking is more recent, they have other products like the Supreme Composite Decking Cleaner to use instead.
When applying this cleaner, no scrubbing is required. You simply apply it to the surface and let it saturate. You will see stains from dirt, mold, and mildew disappearing right away. It can be used on an annual basis to bring your decking back to life and prevent mold and mildew buildup.
This cleaner comes in a concentrated form, which can be diluted and mixed with a small amount of bleach. However, you can get it in a ready-to-use bottle with a hose adapter, which makes it ideal if you want to save yourself a job. Simply spray directly onto the surface and wait for it to work its magic before hosing off. Both options are completely safe for pets and surrounding plant life.
3. RMR-86 Pro Instant Mold Stain and Mildew Stain Remover
This RMR-86 Pro decking cleaner is a heavy-duty product designed to tackle the toughest stains. It uses deep penetrating surfactants that soak into the decking and remove stains caused by mold, mildew, and algae.
The cleaning solution is formulated using Hybrid Ultrapure Sodium Hypochlorite™ that dissolves all types of organic matter such as dirt, mold spores, and moss. This unique formulation means that it is five times stronger than any other contractor-grade composite deck cleaner you can buy right now. Not only that, but it can be used on other wood, concrete, drywall, and tile surfaces around the home.
It is easily applied using a standard pump-up or electric sprayer and there is no scrubbing required. If you want a product that is guaranteed to remove any stains, no matter how deep-set, this is it.
4. Calyptus 45% Pure Super Concentrated Vinegar
Calyptus 45% Pure Super Concentrated Vinegar is actually a very effective deck cleaner for removing mold and mildew. When using vinegar as a cleaner, there are fewer risks of damaging wood or harming surrounding plants. It doesn’t leave behind harmful residues that seep into the soil either, so you don’t have to worry about using it in the garden.
This highly-concentrate vinegar can be mixed with water and used as a decking cleaner with great results. The full bottle will make 9 gallons of vinegar when diluted, so you get a lot of cleaning product for your money.
It will most likely require some scrubbing when applied, but if you are looking for a simple, chemical-free option that will still get rid of mold and mildew, this super concentrated vinegar is ideal.
5. DEFY Composite Deck Cleaner
This DEFY Composite Deck Cleaner is made using an oxygen bleach formula as opposed to chlorine bleach. This means it is safe to use around plants and won’t leave harmful residues on your decking. Chlorine bleach products just bleach out stains without actually removing them, but this deck cleaner will completely eradicate them.
It is also very effective at removing graying caused by weathering.
The product needs to be diluted with water and then applied to the decking with a mop or spray bottle. When diluted, it will clean a total of 500-1000 square feet of decking It only needs 15-20 minutes to soak in before you can scrub it and then rinse off the decking.
This cleaner is suitable for all types of vinyl and composite decks and can be used on aluminum and vinyl siding too.
6. TimberTech Composite DeckCleaner
If you’re looking for a cleaner that’s designed to work with your TimberTech Composite decking, then look no further. This product is made specifically for the company’s flooring solution, but should not be used on TimberTech ReliaBoard, DockSider, or uncapped composite decking.
It tackles dirt and mildew easily but also works great on oil-based substances too. The concentrated formula is easy to dilute and can be used for a full cleaning as well as a simple spot clean on stubborn stains.
The formula is completely biodegradable too and it is guaranteed not to cause damage to TimberTech products, as long as it is used correctly.
7. DeckMAX Concentrated Composite & Wood Deck Cleaner Kit
The DeckMAX composite deck cleaner is suitable for use on all types of composite decking, including Timbertech, Fiberon, and Trex. Many other composite decking cleaners are too harsh for Trex, but this product will clean them perfectly without doing any damage.
It is specially formulated to clean the black stains caused by mold and mildew, as well as the green stains caused by algae growth. The set comes complete with a natural-fiber brush for scrubbing the deck after application. This is a bonus because it saves you money but it also means that you can be sure you are using a suitable tool and you don’t damage your decking.
The DeckMAX cleaning solution is also VOC-free, so it does not contribute to environmental decline and you won’t experience skin irritation or respiratory issues when applying it as you may with strong chemical cleaners.
8. STAR BRITE Non-Skid Deck Cleaner & Protectant
The STAR BRITE Non-Skid Deck Cleaner and Protectant is particularly effective for textured and painted composite decking surfaces. However, it is suitable for use on all kinds of decking as well as fiberglass, vinyl, plastic, rubber, and metal surfaces.
It’s quick to use as it only needs to sit for 2 or 3 minutes before you clean it off. It doesn’t require any scrubbing either as the specialist chelating agents loosen dirt so it can be washed away. That said, it may require a second coat if the decking is particularly dirty.
Unlike some other cleaners, this won’t leave a slippery residue behind afterward, so it’s a good option if you have young children and you want to make your decking area safe.
9. 30 SECONDS Outdoor Cleaner
This 30 seconds outdoor cleaner is the easiest way to clean your decking. It is a bleach-based cleaner capable of killing algae, mold, and mildew, and it comes in a handy spray bottle. You simply have to spray it on, leave it for a few minutes, and then wipe it away. It’s a great multi-purpose outdoor cleaner so you can use it on a variety of surfaces, like gutters and fencing, and it even works inside the house on things like tiles and grout.
This is an excellent cleaner for regular spot cleaning on your decking, but it can be used for routine cleaning and maintenance too, as long as your deck is in relatively good condition.
10. OLYMPIC Premium Deck Cleaner
This OLYMPIC Premium Deck Cleaner is a ready-to-use product that is designed for use on all types of wood, including composite decking. It penetrates deep into the wood and lifts stubborn mold and mildew stains after sitting for 10 minutes, with no scrubbing required.
This product is designed for use as a routine deck cleaner but it is also incredibly effective for cleaning a deck before it is stained. Using this product will ensure that the mildew is not able to come back once the deck has been stained. However, if left to dry or applied too heavily, this cleaner can cause damage to the wood and make the surface rough, so it is important to follow the manufacturer’s directions accurately.
Can You Make Your Own Homemade Composite Deck Cleaner?
Yes, if you do not want to use any of the products listed above, you can make your own deck cleaner with dish soap and water. Simply mix a gallon of water with 2 tablespoons of ammonia-free dish soap in a bucket and use a soft brush to apply it. After allowing it to sit for 10 minutes, rinse off with water. You can also add a small amount of bleach to this solution or vinegar if you want antibacterial or anti-fungal effects.
Alternatively, you can use vinegar and baking soda. Just mix ½ cup of baking soda with a gallon of water and add 50/50 vinegar and water to make the remainder of the solution.
What’s the Best Soft Bristle Broom for Cleaning your Composite Decking? 
Using a good-quality decking brush is the best way to prevent scratches when cleaning your decking. The EVERSPROUT 1.5-3.5 Foot Goliath Deck Stain Brush & Extension Pole Combo is a great option. The 7-inch wide brush holds a large amount of cleaning solution for quick and easy application. The extendable pole also takes a lot of the hard work out of cleaning your deck. 
If you have stubborn stains that you can’t get out, you might need a more durable brush like the 24″ SWOPT Multi-Surface Standard Push Broom. The stiff bristles are good for getting out deep-set stains without damaging the surface of your decking. It’s well-built and the handle is interchangeable, so it’s easy to switch to a longer pole if you need to.
Proper composite decking maintenance is crucial if you want to extend the lifespan of your deck. By using these excellent composite deck cleaners to remove mold and mildew, you can keep your deck area looking amazing and prevent any long-term damage.
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.