How to Pressure Wash a Wood Deck

How to Pressure Wash a Wood Deck

When it’s time to clean your wood deck in preparation for refinishing, a chemical deck brightener used by hand may not be sufficient for a thorough cleaning, however, a pressure washer would.

A pressure washer is simple equipment that can effectively clean with water alone. However, if not employed appropriately, it might wreck your deck. This instrument is strong enough to engrave masonry, but in the correct hands, it may also be used to wash siding. If you apply excessive jet pressure or position the nozzle too close to the surface of your deck, you might badly etch the wood and cause the fibers to split. Take some time to familiarise yourself with the machine before unleashing its cleaning power on the deck.

What You’ll Need

Equipment / Tools

  • A pressure washer with a fan tip or rotating tip
  • Sheets of plastic (optional)
  • Random orbit sander (optional)


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


Select a Tip and Pressure Setting

Select the suitable spray tip and pressure setting for your application:

Utilise the lowest effective pressure achievable. The pressure for mild wood (such as cedar or pine) should be between 500 and 600 pounds per square inch (psi); for stronger woods, you should not exceed 1,200 psi. Use a fan tip with a spread of 40 to 60 degrees. A revolving tip is also acceptable if used with care.

Test the Pressure Washer Settings:

Utilizing a pressure washer requires some practice. Examine your pressure and its efficacy in an inconspicuous spot, such as a stair tread or a corner. If you must replace a piece of wood because you etched it, it is simpler to repair a stair tread than a surface deck board.

Starting pressure should be between 500 and 600 psi. Gradually increase the pressure until you find the optimal level for effective cleaning.

Power Wash the Deck:

Engage the trigger while holding the wand tip a few feet from the surface of the deck, then lower the wand as necessary. If you come closer than 6 inches, you could potentially damage the wood.

Clean the deck using a sweeping motion, and avoid pivoting your arm, as this will result in an irregular distance between the spray tip and the deck surface. Move your arm laterally back and forth to attempt to maintain a constant distance.

Deck boards should be cleaned from the house outward. Work with the grain by feathering the spray along the length of the deck boards and gently overlapping each section. The objective is to obtain uniform cleaning without “hot spots” or discernible cleaning edges.

Apply a Chemical Stripper/Brightener (Optional):

Washing the wood with a solution that contains sodium hydroxide will help brighten it if it has been seriously discolored or is soiled with mildew stains. You should look for a product that was designed specifically for whitening deck wood and that can be used in a pressure washer, and you should also check to make sure that your pressure washer has an entrance for the cleaning solution.

Perform the mixing of the solution in accordance with the instructions provided by the manufacturer. First, apply the stripper solution in the same way as you would when using plain water for high-pressure washing, and then rinse the area with plain water. As a general rule, you will need to give the deck a thorough sanding before applying a new coat of stain or sealant to the wood. This is because stripper and brightener solutions have a tendency to roughen the wood fibers.

Sanding After Washing

In an ideal world, power washing a wooden deck would not destroy the wood or erode or etch the softwood fibers. However, when the wood is exposed to moisture, the fibers in the wood may become elevated, resulting in a surface that is rough. Handrails are particularly susceptible to this issue since the elevated fibers can cause splinters and require some sanding before they are safe to use.

In order to solve this issue, you can choose between a few different approaches. If you did an excellent job of power washing with very little damage and all you want to do is clean the deck, you might be able to get away with only doing some spot sanding here and there instead of sanding the entire deck. Sanding the entire deck is necessary if you plan to refinish (re-stain or re-seal) the deck since this will generate smooth boards with very little to no splintering. However, if you do not plan to refinish the deck, you can skip this step. Sanding opens up the pores in the wood, allowing it to consistently absorb the sealer or stain that has been applied. Before beginning to sand the wood, be sure that it is completely dry.

When you are sanding, you should avoid using very fine sandpaper since this might cause the pores in the wood to become clogged, which will prevent the stain or sealer from easily penetrating the wood. Sandpaper with a grit size of no more than 100 should be used for the railing. Sandpaper with a grit range of 60 to 80 should be used on the deck surface itself. A random orbit sander that has a sanding pad that is 5 inches in diameter is the type of sander that is ideal for use on a wood deck. Learn more about apk

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