Effective Tips for Cleaning Composite Decking

Last Edited 4/12/24


Designing and building your outdoor space and deck to fit your family’s needs can be both fun and exciting. Making sure you know how to care for your deck is important for making sure it has a long life.

Composite decking is a great alternative to traditional wood decking. It is a durable, man-made building material that is an equal mix of recycled wood fibers and recycled plastic. Not only does it have a longer life span than traditional wood decking, but it’s also a low-maintenance option to make your backyard shine all summer long. 

Tools for Cleaning Composite Decking

If your deck isn’t too dirty, soap and water will do. If it’s been a while, you may want to use a commercial cleaning product; always read the manufacturer’s instructions before using any commercial deck cleaner.

• Broom
• Bucket
• Mild dish soap
• Soft-bristled brush
• Water hose
• Deck brightener product containing oxalic acid
• Pressure washer (optional)
• Leaf blower (optional)

How to Clean Composite Decking

Make your deck shine with these tips from Mr. Handyman. These are general cleaning tips, and every deck isn’t the same. Since there are many different types of composite decking materials, we recommend reading the manufacturer’s cleaning recommendations before following ours. In some cases, they may have certain requirements. 

Before beginning, use tarps to cover and protect sensitive landscaping plants that may react to any chemicals used to clean the deck.

• Sweep the Deck. Sweep off any surface debris such as leaves, pine needles, and dirt from the deck.
• Pre-rinse the Deck. Rinse the deck off with a garden hose or power washer. If you decide to use a power washer, keep it on the lowest setting and at least 8 inches from the surface of the deck. This will keep the decking from becoming damaged by the power washer.
• Spray with Soapy Water and Scrub. Spray the deck thoroughly with soapy water, using long sweeping motions and following the length of the boards. Gently scrub the deck with a soft-bristled brush to remove any built-up dirt on the deck.
• Rinse with Clean Water. Once the deck has been scrubbed, rinse thoroughly with clean water, ensuring all the soapy water has been rinsed clear from the deck.

How to Clean Mold and Mildew from Composite Decking

Mold and mildew aren’t just an eyesore, they can be hazards to your health and can even shorten the life span of many composite deck boards. Mold and mildew can sometimes make composite deck boards slippery, so use caution and wear good shoes while cleaning. Use these tips to remove mold and mildew stains from your deck boards.

• Sweep the Deck. Sweep off any surface debris such as leaves, pine needles, and dirt from the deck.
• Pre-Rinse the Deck. Rinse the deck off with a garden hose or power washer. If you decide to use a power washer, keep it on the lowest setting and at least 8 inches from the surface of the deck. This will keep the decking from becoming damaged by the power washer.
• Spray Mildew and Mold with Vinegar Solution. Mix 2 parts vinegar and one part water together in either a spray bottle or a bucket. Spray or pour the solution directly onto the mildew or mold.
• Add Baking Soda. Sprinkle baking soda on the mildew or mold with the vinegar solution and let sit for 20 minutes. This will allow the solution to break up the mildew or mold, making it easier to remove. Scrub the area with a soft-bristled brush to remove any leftover mildew and mold.
• Rinse with Clean Water. Once the deck has been scrubbed, rinse thoroughly with clean water to remove any leftover debris or dirt.

Don’t Make These Mistakes

Avoid these common mistakes to make cleaning your deck easier.

• Using the Wrong Cleaner. Composite decking can be quite porous, so it’s important to use the correct cleaner on your deck. Avoiding using any deck cleaner that has bleach in it as it can be extremely corrosive. Instead, use an oxygenated cleaner that can reach deep into the material and clean the inside of the deck as well as the outside. Use a cleaner that is safe for the environment. This will help protect any plants you have around your deck.
• Don’t Forget the Gaps. Dirt and debris can build up over time in the gaps between the boards. Keep these clear to allow for air to pass through them, allowing the underside of the deck to remain dry. Doing so will help reduce the amount of mildew and mold that might potentially be growing on the underside of the deck.
• Don’t Use the Wrong Tools. For regular cleaning, a broom and garden hose should be sufficient for cleaning the deck. But when it comes time for a deeper clean, make sure to use a soft-bristled brush for scrubbing the deck boards. Using a soft-bristled brush will keep the decking from becoming scratched and helps to keep dirt from getting ground into the grooves. For those with composite decks in colder climates, make sure you use a plastic shovel for snow removal rather than a metal one!

Professional Help When You Need It

If your deck becomes damaged and you need help replacing old boards or for any other home improvement projects, contact Mr. Handyman! Request service online or call us today!