Is It a Good Idea to Use a Power Washer on a Wood Deck or Composite Deck Regularly?

Are you overwhelmed by the dirty state of your deck? Has a mysterious gunk on the deck’s surface started to ruin your outdoor space’s once-beautiful appearance? You might be tempted to resolve the issue by taking a power washer to your deck and aggressively spraying it down, but power washers can actually do more harm than good for most deck materials.

Damage Caused by Power Washing Your Deck

Wood decks are especially vulnerable to power washing because the pressure exerted by the power washer can lead to splintering. If there is any area on the deck where the wood is already beginning to split apart, power washing it will exacerbate the problem and cause the split area to expand.

Wood isn’t the only decking material that can be permanently damaged by power washing. Softer materials, such as PVC, can essentially be engraved by a power washer if the pressure is set too high.

It’s also a bad idea to use a power washer on a composite deck because the power washer can actually take chips out of the composite material. To make matters even worse, damage caused by power washing is not typically covered in the warranties for composite decks. So, if you do damage your deck beyond repair, you’ll be paying out of pocket to fix it.

When Is Power Washing OK?

There are a few situations when it might be OK to use a power washer on your deck. Decks made of ASA, which is essentially a high-end capstock, tend to be a little more forgiving when power washed. Wood and composite decks can also sometimes be cleaned with a power washer but only if you have a professional doing it.

When choosing a professional to power wash your deck, don’t just choose someone from your local power washing company. Choose someone who specifically has experience power washing decks. He or she should use a relatively low pressure setting (probably no more than 1,500 PSI) and a wide fan. The power washer should also be held at least two feet off the ground. This can be a good way to deep clean your deck and to get embedded dirt out. Don't have a professional power wash your deck too frequently, though. (Once a year is usually sufficient.) For the most part, you can regularly clean your deck without using a power washer.

Cleaning Your Deck without a Power Washer

The key to keeping your deck in great condition for years is to stay on top of the cleaning. If you haven’t already made washing your deck a part of your regular household cleaning routine, it’s time to start. At a minimum, set a goal to clean your deck every two weeks.

Fortunately, basic deck cleaning isn’t too complicated. The only materials you’ll need are a broom, a hose, a bristle brush, and a biodegradable cleaning solution. Dish soap should work fine on your deck, although some homeowners use a mixture of powdered laundry detergent (without bleach) and water.

Start by clearing any outdoor furniture and other accessories out of the way. Sweep any debris off your deck. If leaves frequently fall on your deck, you might need to sweep it off more frequently. When leaves get wet, they can leave a hard-to-clean residue on the deck’s surface.

Once you have swept your deck, begin cleaning it using water, your cleaning solution, and a bristle brush. Test your cleaning solution on a small, inconspicuous patch of your deck first. This ensures the solution you're using doesn’t leave a stain. Once you start scrubbing the entire deck, you’ll need to apply some elbow grease, but don’t scrub so hard that you scratch or splinter your decking material.

After scrubbing your deck, rinse it off with your hose, and then simply let it dry before moving furniture and other items back. This cleaning routine will keep your deck looking great and will prevent you from needing to frequently reach for the power washer.

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