Can You Power Wash a Composite Deck?

Last Update:

We use affiliate links and may receive a small commission on purchases. Learn more

power wash composite deck

Composite decking is a great material for people who want the look of wood without the hassle. 

Composite has longevity and durability that wood can’t match and comes in all kinds of colors and styles. Modern composite has a look that is so similar to wood you would have no idea it wasn’t. 

However, it can get complicated when the time comes to wash the deck. 

Unlike wood, composite can be sensitive to pressure washing and doing it too hard can open the pores. When this happens, you can end up damaging the composite and opening it up to deterioration. 

While it is recommended that you wash composite decking manually with a hose, pressure washing can be done. All it takes is a little bit of preparation and careful planning. 

In this article, we have laid out what you need to do in order to pressure wash a composite deck. By following these instructions, you can keep your deck in good shape for longer. 

Power Washing a Composite Deck: Basic Idea 

Power washing a composite deck isn’t that different from doing it on a wood deck. It just requires a few precautions and steps. These include: 

  • Set the PSI 
  • Spray with soap 
  • Rinse the deck 
  • Dry the surface thoroughly 

Mistakes to Avoid When Power Washing a Composite Deck

mistake to avoid when power washing composite deck

The number one mistake you want to avoid when power washing composite decking is too much pressure. 

Many people want the fast cleaning power of a power washer, so they end up setting it too high. When you do this with composite, though, the coating can open up and break the seal. 

The protective coating on composite decking is what makes it so durable against snow and rain. Although you might not notice the damage right away, as time goes on, the color may start to fade.

If you are not using a power washer to clean your deck, you should avoid harsh brushes. 

Use a soft brush to clean your composite deck. Harsh brushes can also open up the pores in the composite and cause damage down the line.  

Set Your PSI 

Before you begin power washing your composite deck, you will want to set your PSI. 

The PSI is the amount of force that the water comes out of the washer at. It will be adjustable with nearly every power washer, so it is important to take note of it. 

The PSI for composite decking should never be above 3,100. While it may take a little more elbow grease to get it clean, it will ensure that the deck isn’t compromised. 

Do a couple tests of the pressure on an inconspicuous area before doing the whole deck. This will give you an idea of what the pressure is like and how to handle it. 

Spray the Deck 

Once you have set the PSI, you can then put soap in the soap dispenser. 

For most decks, you can use a few drops of liquid dish soap in the dispenser. This will be a gentle, non-abrasive solution that will still get the dirt off the deck. 

Make sure you are using a fan nozzle on the washer as well. This spreads out the spray and ensures that there are no hot spots of too much pressure. 

As you spray, keep the nozzle no closer than eight inches from the deck. Work in smooth motions along the printed grain of the composite. 

Rinse Thoroughly

rinse thoroughly
After you have sprayed down the deck, then you can rinse it off. 

Rinse the dirty water off the deck with a standard garden hose. If you don’t get this water off the deck, it will leave a film. 

This will also give you an opportunity to make sure you cleaned every area of the deck. Look for any missed spots and spot clean them with the pressure washer. 

Dry With a Mop 

Once the deck is rinsed off, it is a good idea to dry it as thoroughly as possible. This will prevent water spots as the water dries in the sun. 

You can use a regular mop to mop up all the water on the deck. 

If you leave it without drying, you could end up with calcium or other mineral deposits. These can cause a reaction on the surface of the composite decking and stain it. 

Frequently Asked Questions

faq power wash composite deck

  • Can you clean a composite deck with vinegar?

If you are just doing some spot cleaning, you can use vinegar to clean your composite deck. 

Mix a solution of 50 percent water and 50 percent vinegar. Then, using a soft brush, work the vinegar into the composite and rinse it with a hose. 

  • How long do composite decks last?

If properly cared for, a composite deck can last upwards of 30 years. 

This is one of the reasons they are gaining in popularity over wood decks. A wood deck will usually need to be replaced after 10 years. 

  • Is a composite deck worth the money?

If you are looking for longevity, a composite deck is absolutely worth the money. 

By lasting for a long time, you could end up saving a lot of money in the long run. Composite decks also hold their color and don’t fade as much as wood decks do. 


By taking care of your composite deck, you can be sure that it will last for years to come. 

Keeping it clean will keep dirt and debris from getting stuck on it and causing deterioration. By following the above steps, you can protect your deck and prevent any premature aging. 

Photo of author


Michael J. O’Connor is a writer and marketing specialist from the Bay Area of California. A graduate of Sonoma State’s Creative Writing program, he spent many years as a contractor and carpet layer, learning the ins and outs of flooring and general contracting. When he’s not typing away at his desk, he enjoys hiking with his dogs, woodworking and collecting rare books. See full biography here.

Leave a Comment

nineteen − four =