How to Pressure Wash a Wood Deck


A chemical deck cleaner applied by hand may not be sufficient to deep clean your wood deck. However, a pressure washer will.

A pressure washer is an easy machine that cleans with water. If it isn’t used correctly, the pressure washer can cause damage to your deck. Although it is powerful enough for etching brick, the tool can also be used to clean siding. You can damage the wood fibers if you apply too much pressure to it or keep the tip too close. Before you start cleaning your deck, take some time to get to know the machine.

You can now watch this video to learn how to properly pressure-wash a wood deck


You can use a pressure washer for many purposes around your home. However, if you don’t want one of your own, you can rent one at a tool rental shop or home improvement center. A rental cost for a day can range from $40 to $100.

What you’ll need

Equipment / Tools

  • Pressure washer with fan tip or rotating tip
  • Plastic sheets (optional).
  • Random orbit sander (optional)


  • Deck stripper/brightener (optional)
  • Sandpaper (optional)


Choose a Pressure and Tip Setting

Select the right pressure setting and spray tip to suit your application

The lowest pressure is the most effective. For soft woods like cedar and pine, pressure should be between 500 to 600 pounds per sq inch (psi). Harder woods can tolerate higher pressures but not more than 1,200 PSI.

A fan tip should have a spread of 40-60 degrees. If you are careful, a rotating tip may also be suitable.

Check the Pressure Washer Settings

It takes some practice to use a pressure washer. You can test your pressure washer’s effectiveness in a small area such as a corner or stair tread. A stair tread can be used to replace wood pieces that have been etched.

You can start with a pressure of 500 to 600 PSI. You can increase the pressure gradually until you reach the ideal setting for cleaning.

Power wash the deck

Hold the trigger a few feet from the deck surface. Then lower the wand as necessary. You should not get any closer than 6 inches to avoid damaging the wood.

Use a broad motion to clean the deck. Avoid pivoting with your arm. This will cause an uneven distance between the spray tip’s edge and the deck surface. You can maintain a consistent distance between the spray tip and the deck surface by moving your arm laterally.

The deck boards should be removed from the house. You can work with the grain by feathering your spray along the deck boards and slightly overlapping each area. You want to ensure even cleaning without any “hot spots” or visible edges.

Use a Chemical Stripper/Brightener (Optional).

A deck-cleaning solution containing sodium hydroxide may be used to brighten wood that has been stained or darkened. Make sure you have a product that is designed to brighten deck wood.

Mix the solution according to the manufacturer’s instructions. The stripper solution should be applied in the same way as pressure washing, using plain water. Rinse the container with plain water and then wash again. You will need to sand the deck thoroughly before sealing or re-staining the wood.


The chemicals in deck strippers/brighteners are toxic to plants, so make sure to shield shrubs and garden plants around the deck with sheets of plastic before using the stripper with a pressure sprayer.

Sanding after washing

Power washing a wood deck won’t damage the wood or etch the softwood fibers. Wood can become brittle if it gets wet. Handrails are prone to this problem, as the raised fibers can cause splinters. Before sanding, ensure that the wood is dry.

There are a few options to fix this problem. You may be able do a spot-sanding if you have done a good job power washing the deck with minimal damage. If you plan to refinish the deck (re-stain, reseal), you will need to sand all of it to make smooth boards that are free from splintering. Sanding opens the pores of the wood, allowing it to absorb the stain or sealer more consistently.

Use fine sandpaper when sanding. This can cause wood pores to clog and prevent stain/sealer soaking in. Use no finer than 100-grit for the handrail. Use 60- to 80-grit for the deck surface. A random orbit sander equipped with a 5-inch sanding plate is the best for wood decks.

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