How to Clean a Composite Deck

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how to clean a composite deck

Composite decking contains a mixture of wood and plastic. Because of this blend, this type of decking is more durable, easier to clean, and requires less maintenance than traditional wood options.

But that doesn’t mean composite decks are no maintenance. If you want your deck to last and look good, you need to take care of it.

Here’s how to clean a composite deck. You should sweep or hose debris off your composite deck weekly or as needed. To deep clean your deck, start by hosing it down. Next, use dish soap and a long-handled, soft-bristled brush to give it a gentle scrub. Afterward, thoroughly rinse. 

Best Way to Clean a Composite Deck: Detailed Step-by-Step

how to clean composite deck

You can keep your deck clean by sweeping or hosing it off regularly. If you need to deep clean try one of these methods.

Pressure Washer Method

Yes, you can pressure wash a composite deck, but you’ll need to look at the recommended PSI setting for your particular brand. A general rule of thumb and the guidelines for Trex is 3,100 PSI or less, which is still fairly high-pressure.

Here’s what to do:

  • If you’re using soap put it in the power washer and spray the deck
  • Gently scrub with a soft-bristled brush
  • Use your power washer (without soap) to rinse the deck off
You’ll want to keep your power washer at least 8 inches away from the boards and completely rinse the soap off. If you don’t thoroughly rinse, the dirty water will dry on the deck leaving it with spots.

Scrub Brush Method

The next method is the safest for cleaning composite decks and easy to do. 

Here are the steps to take:

  • Sweep or hose debris off the deck
  • Wet the deck with a hose
  • Scrub each board with a soft-bristled brush and dish soap
  • Thoroughly rinse
Again, rinsing is essential. Failure to do so will leave dirt and soap spots all over the deck when it dries.

How to Remove Hard Water Stains from a Composite Deck

If you have hard water stains left on your deck, they’re most likely coming from the water you’re cleaning it off, which makes getting rid of them hard.

You can try getting rid of these stains by cleaning the deck with a half white distilled vinegar, half water solution. Once clean, thoroughly rinse off the deck and then dry it with a towel. If you don’t towel dry, the spots are likely to show up again.

What are the Best Cleaners for Composite Decks?

If you’re cleaning a composite deck, one of the best cleaners is dish soap. You can also clean the deck with vinegar. 

If you’d rather use a store-bought cleaner made for decks, try one of these:

You can find many more cleaners at your local home improvement store. Just look for one that says it’s safe for composite materials.

Frequently Asked Questions

faq how to clean composite deck

Can you use Dawn to clean a composite deck?

Yes, Dawn is an excellent choice for cleaning a composite deck. Just about any dish soap will be safe to use.

How do you remove mildew from a composite deck?

The best way to remove mildew from a composite deck is to hose it down and scrub it with soap and a soft-bristled brush and rinse afterward. You can also use a power washer to get rid of mildew if you prefer.

Why is my composite deck turning white?

If you’re noticing white spots on your composite deck, the seal has likely worn down, and the sun is bleaching the boards in areas. You’ll need to contact your manufacturer for specific advice.


Composite decks are very durable and require little maintenance. Sweep it or hose it off regularly. If you need to deep clean, use dish soap and a soft-bristled.

Alternatively, if you have a power washer, you can also use it to do a deep clean. Just be sure to check for the recommended PSI for your particular brand of decking.

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Katie Barton lives with her husband and three daughters in an 1800’s style log cabin in southern Ohio. She thinks cleaning is relaxing and is considered the organizing go-to person by her family and friends. She runs the blog Cabin Lane where she shares about cleaning, decluttering, and minimalism. See full biography here.

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