How to Pressure Wash a Deck

Pressure washing your deck can remove years of stains, weathering and discoloration in just a few hours. We’ll show you how to pressure wash a deck step by step, with detailed instructions for both wood and composite boards, plus optional instructions for staining.

Wood deck cleaned with a pressure washer

Tools and materials for the job

The list below contains all the tools and materials you may need to restore a deck from start to finish. Some items are necessary, while others are optional depending on your circumstances.

  • Pressure washer. Wood decks should be cleaned with moderate pressure, while composite decks should be cleaned with low pressure, so you can use any pressure washer to clean composite (as long as you choose the right nozzle, which we’ll discuss later), but you generally need at least 2,000 PSI to clean wood.
  • Cleaner, brightener. Decks should be treated with two detergents, cleaner and brightener, and both should be specific to your deck material. To remove old stain or paint, you may need a stripper, which would be used instead of a cleaner (strippers are essentially heavy-duty cleaners). Remember, only use cleaning solutions that are pressure washer safe.
  • Deck brush. Wood and composite are porous materials, so detergent should be scrubbed into the surface with a deck brush to loosen embedded grime. The brush should have synthetic bristles for chemical resistance, with stiff bristles for wood and soft for composite.
  • Sander, sandpaper. Decks should be sanded after pressure washing to reduce any raised fibers and open the material’s pores for stain absorption. You can use any type of sander, but you need 60- or 80-grit sandpaper for wood and 220- or 240-grit for composite.
  • Push broom. Loose dirt and dust should be swept before washing and after sanding, and while you can technically use your deck brush for sweeping, push brooms are more efficient.
  • Safety gear. Pressure washing can cause injuries, with one relevant hazard being projectile deck fibers, so you should have safety glasses, enclosed shoes, gloves and full-length clothing.
  • Putty knife (optional). If your pressure washer won’t remove tough grime between boards, you may need to scrape it out manually with a putty knife or another similar tool.
  • Stain, paint brush (optional). If you plan to stain your deck after pressure washing, you generally need about one gallon of stain per 100 ft2 (assuming you will apply two coats, which is standard), plus you need a paint brush or pad for application.
  • Plastic sheeting, painter’s tape (optional). If your deck has any nearby doors, fixtures or other unmovable objects that could be dirtied or damaged, consider covering them with plastic sheeting and painter’s tape for temporary protection.
Wood deck before and after pressure washing

Steps to pressure wash a deck

If this is your first time using a pressure washer, learn the basics in our article, How to Use a Pressure Washer. When you’re ready, continue with the steps below to pressure wash your deck.

  1. Prepare the area. Remove any objects that are blocking the deck, like furniture or pottery. Use your plastic sheeting and painter’s tape to cover any unmovable objects, like doors or windows.
  2. Sweep the deck. Use your push broom to sweep away as much loose dirt as possible.
  3. Start your pressure washer. Put on your safety gear. Set your pressure washer in one corner of the deck, or choose a stable surface off the deck, if possible. Connect your garden hose, high pressure hose and spray gun, then start your pressure washer.
  4. Apply cleaner. Fill your detergent tank with cleaner (depending on your pressure washer, you may have an onboard detergent tank or you may need to siphon from an external tank). When ready, connect the 65° nozzle and apply cleaner to the entire deck. Allow the solution to soak for 5-10 minutes. During this period, use your deck brush to scrub the surface.
  5. Rinse the deck. Connect the 25° nozzle and rinse the cleaner from the deck using plain water.
  6. Apply brightener. Flush the cleaner from your detergent tank and fill it with brightener (if you’re using an external tank, you can simply swap to a new tank). When ready, connect the 65° nozzle and apply brightener to the entire deck. Allow the solution to soak for 5-10 minutes.
  7. Rinse again. Connect the 40° nozzle and rinse the brightener from the deck using plain water.
  8. Sand the deck. Allow the deck to dry for at least 24 hours before sanding. When ready, use your sander to lightly sand the entire deck with the appropriate sandpaper for your material.
  9. Sweep again. Use your push broom to sweep away as much sanding dust as possible.
  10. Apply stain. Stir the stain for 20-30 seconds, or until you have an even color consistency. When ready, use your paint brush or pad to apply stain, working in sets of 2-3 boards at a time. Apply two thin coats to each set before moving on to the next (two coats is standard, but depending on your stain, you may need to apply more or less coats). Allow the stain to dry for 24-72 hours before using your deck again.

Frequently asked questions about pressure washing a deck

The most common questions about pressure washing a deck are answered here. For additional help, you can reach out to us at any time. For questions about specific products, we’re happy to offer advice, but depending on the question, you may need to contact the manufacturer.

How much does it cost to pressure wash a deck?

This depends on your location and the size, material and condition of your deck. Generally, the cost to pressure wash a deck is between $0.50-0.75 per square foot, which includes labor and supplies. This equates to $150-225 for the average backyard deck, assuming the size is around 300 ft2. Keep in mind, this does not include stain. Expect an additional $0.25-0.50 per square foot for staining or sealing.

Compare the professional cost above with the cost of doing it yourself. Based on the tools and materials we listed earlier, the cost would be between $500-600, assuming every item is purchased brand new. If you already own any of the items on the list, or you plan to rent or borrow a pressure washer and sander instead of purchasing them, the cost could easily reduce to under $200.

How long should you wait to stain your deck after pressure washing?

This depends on the product. Generally, stain should be applied once the deck is dry, which can take 24-72 hours. However, some stains can be applied within a few hours of pressure washing. Regardless, sanding can only be completed once the deck is dry, and that comes before staining, so expect to do it then.