How to Clean Composite Decking in 5 Easy Steps

By
Kate Van Pelt
Kate Van Pelt, home decor and home improvement expert for The Spruce
Kate Van Pelt
Kate Van Pelt is a contributing writer for The Spruce, based in the PNW. Kate has been a full-time digital content creator for nearly a decade, covering everything from home decor to personal finance.
Learn more about The Spruce's Editorial Process
Updated on 08/26/23
Fact checked by Marcus Reeves
Composite deck with railing against house.

WoodysPhotos / Getty Images

In This Article
Project Overview
  • Working Time: 15 mins - 1 hr
  • Total Time: 15 mins - 3 hrs
  • Skill Level: Beginner
  • Estimated Cost: $0-25

When the weather is inviting, you'll want to spend more time outside, but the mildew, pollen, pine needles, and other dirt and debris that's collected on your composite decking can be a massive distraction. Fortunately, composite decking is durable, low-maintenance, and very easy to clean. In fact, you won't need much more than soap and water.

Use the following five-tep guide to learn how to clean composite decking and keep it gleaming.

How Often to Clean Your Composite Decking

Composite decking is designed to last for years through all sorts of weather, so you won't have to clean it too often. Experts typically recommend cleaning your composite decking on a semi-annual basis. Depending on your geographic location and frequency of use, one or two cleanings each year should suffice. The best time to clean is right after the hard winter months as you're heading into spring. However, you should sweep or leaf blow at least monthly to prevent build-up. Also, pay attention to any grease or mildew stains that appear and be sure to clean them immediately to prevent tough stains.

Before You Begin

While the suggested cleaning regimen for composite decks is similar between brands, always check the manufacturer's care and maintenance recommendations for your specific decking before you begin cleaning.

For instance, some online cleaning guides suggest using a pressure washer on your composite decking. If your composite decking is in need of a deeper clean, you may prefer to use stronger tools like a pressure washer or rotary cleaner. Generally, composite decking can handle pressure washers, when used with no greater than 1500 psi and a fan attachment held no closer than 6 inches from the decking surface. However, pressure washers can also damage composite decking, so it's important to check the manufacturer's instructions first.

What You'll Need

Equipment / Tools

  • 5-gallon bucket
  • Outdoor push broom
  • Soft-bristle brush
  • Hose
  • Putty knife or flathead screwdriver

Materials

  • Biodegradable dish detergent

Instructions

How to Clean Your Composite Decking With Soap and Water

  1. Clear the Decking Surface

    Before you begin covering your deck with soap and water, clear away any furniture, flower pots, grills, and other decorative items. If your furniture and pots are too heavy to move with ease, cover them with tarps.

  2. Sweep or Leaf Blow

    After you've removed the furniture and decor, start your cleaning regimen by removing any large or loose debris, such as sticks, leaves, and dirt. Use a putty knife or flathead screwdriver to free any debris that's trapped between your deck boards, then go over the entire decking surface with a broom or leaf blower.

  3. Scrub Decking With Soap and Water

    After you've rid your deck of dirt and debris, it's time for a more thorough cleaning. Add half a cup of biodegradable dish detergent to a 5-gallon bucket, then use your hose to fill the bucket halfway with water.

    Next, pour a thin layer of the solution over a small section of your decking (a 5 foot by 5 foot square, for instance). Use a bristle brush or an outdoor push broom to scrub away caked-on dirt and stains, following the direction of the board's grain (lengthwise, going up and down).

    Tip

    To tackle extra tough debris, scrub your decking a second time going against the grain on your next pass. Adjust the size of your brush to access corners and edges.

  4. Rinse Away Soap

    After scrubbing your first 5x5 section, use a hose to rinse away the soap and suds. Move onto the next section of your deck, repeating steps three and four until you've completed the entire deck surface. Finish with a final, thorough rinse over the entire deck, to clear any leftover residue from the soap.

    Tip

    It's important to work in small sections to prevent your detergent solution from drying and leaving a cloudy film over the top of your decking.

  5. Air Dry and Put Everything Back

    To finish out your cleaning, leave the deck for a couple hours or so to dry naturally in the sun. Once it's done drying, return your furniture and other outdoor decor to their proper spots or remove the tarps.

Tips to Keep Your Composite Decking Clean Longer

  • Clear your deck of leaves, pollen, and any other debris regularly (once or twice a month) to prevent build-up.
  • Clean mud and mold as soon as it appears.
  • Scrub underneath your flower pots every couple of months to prevent stains.
  • If you use a grill or similar cooking appliance on your deck, pay close attention to any grease spills or charcoal smudges and clean them immediately.
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