How to Clean a Composite Deck Properly

Composite is a popular decking material that is water, stain, scratch, and mold resistant. Although similar in appearance and workability to wood, composite is stronger, highly durable and with low-maintenance requirements.

Cleaning is one way of making a composite deck to look its best and remain in good shape years to come. Let us learn how to clean a composite deck, remove mildew, mold and stains.

How to Clean a Composite Decking

Cleaning a composite decking is an easy process as compared to cleaning of wood decking, paving slabs and concrete surfaces. You simply use warm soapy water, a soft scrub and a hose. Tough and sticky stains can be cleaned using a recommended composite deck cleaner.

While mildew and mold won’t damage a composite deck, they will automatically steal its beauty. Mold and mildew are also a hazard to your health.

Pollen, leaves, debris and soil can block deck gaps and prevent rainwater from draining properly, thus promoting growth of mold, deck stains and even rotting and warping of the boards.

Summer or during a sunny day serves as the best time to give your decking a thorough cleaning. Since you are working in direct sunlight, cleaning in small sections helps in preventing dirty water and suds from drying onto the surface before you reach out to wash and rinse them away.


  1. Move all items sitting on your decking including furniture, rugs, chairs, tables, barbeque grills and potted plants. This will make the whole cleaning process faster and effortless.
  2. Get rid of dirt and debris from your decking using a soft bristle brush or a vacuum cleaner. Hose down through the gaps to remove trapped dirt and debris
  3. Mix some soap with warm water in a bucket and use it with a soft brush to scrub the composite decking. Alternatively you can use a commercial deck cleaner.
  4. Extend the cleaning to deck railing as you scrub them with a soft scouring pad and your soapy water.
  5. Follow with a hose and allow the decking to dry out naturally in the sun as you enjoy the shine.

Sweeping and cleaning with soapy water will get rid of debris and most surface dirt and stains. However, oil, grease and some food and beverage stains may require use of a deck cleaner.

While there are plenty of such products on the market, stick to what the composite decking manufacturer has recommended to avoid causing any damage.

Should I Pressure Wash my Deck?

A pressure washer can cautiously be used on a capped composite decking that usually has a polymer protective shell at the core.

Uncapped composite is made of soft materials that can damage when subjected to intense pressure and thus not suitable for washing with a pressure washer.

To use a pressure a washer without damaging the protective coatings on the decking, here are the dos and don’ts

  • Never exceed 1,500 PSI when pressure washing your composite decking
  • Your power washer should be at least 30cm away from the deck
  • Place a fan tip on your power washer to make the spray more gentle
  • Wash along with the grain of the decking boards

How to remove snow and ice from composite decking

During winter, snow and ice will form on your composite decking. If you still want to use your decking, you can comfortable remove the snow without damaging the deck surface. Here is how to do it safely:

  1. Thick layer of snow can be removed with a shovel. However, this must be done with the right type of a shovel. Using a shovel with metal cutting edge will cut and damage your composite decking. Ideally, use a shovel with a plastic or rubber edge to safely remove the snow.
  2. Light snow on a composite decking can safely be removed using a broom or a leaf blower. If you have a snow blower, you may be tempted to use but this will be a bad idea. A snow blower will definitely cut and damage your composite decking.
  3. Recommended ice melts can also be used for getting rid of ice on a composite decking. Calcium-chloride is an example of a safe and effective compound you can use for melting ice on your decking. Sodium chloride rock salt should not be used for ice melting. The granules may leave permanent unsightly marks on the surface of your decking.

In addition to cleaning, there are a number of things you can do to prolong the life of your composite decking.

  • Always keep the deck surface dry and clean as much as you can. This prevents mold, mildew and stain problems.
  • Check and fix any drainage issues promptly. A deck surface should be at least 6 inches above the ground. This helps in both air ventilation and draining matters.
  • Gaps should be free from debris all the time. This ensures proper drainage after a downpour

Soapy water and a soft scrub is highly effective for cleaning a composite decking. Unlike wood decking, composite does not attract stains easily and it cleans effortlessly. Do not use any other chemical cleaner to clean your composite decking unless it is recommended by the boards manufacturer.

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