Deck Power Washing
An Important Step Before Staining

When properly performed, deck power washing accomplishes more than a simple cleaning. This ranges from opening the pores of the wood to removing old finishes from the decks surfaces.

Every surface benefits from a good cleaning before application of a finish. Possibly a wood deck benefits the most.

Benefits of Deck Power Washing

• Safely removes dirt and dust.
• Opens wood pores allowing deep penetration of the deck stain or finish.
• Fully rinse deck cleaners or wood brighteners. Much better than a garden hose.
• Alone can remove discoloration from the various deck surfaces.
• Safely strip old finishes, including stains and peeling paint.

A good cleaning, with or without chemicals, is necessary after major sanding of a wood deck and before any staining can take place. Anything less will produce inferior results.

Proper Deck Power Washing Techniques

Power washing a deck requires the use of a pressure washer producing highly pressurized water and can damage the wood surface if performed improperly.

Use a sweeping motion. Pull the trigger at the beginning of the motion. This will direct the first burst of pressurized water at a low angle to the surface, away from the wood deck floor. If you don't do this a deep straight mark will form in the wood.

After the trigger has been pulled continue to walk the pressurized spray from one end of the deck to the other without stopping. If you must stop, sweep the nozzle away from the deck surface then release the trigger. Wash 2 boards at a time. Overlapping each pass of the pressurized spray onto previously cleaned wood.

Two different techniques are used to wash a deck depending on the condition and amount of preparation you plan on doing.

Deck Power Washing After Sanding

If you opted for a thorough sanding of the wood deck floor, highly recommended, then cleaning of the house and deck surfaces will be needed.

This cleaning is to remove the dust and open up the wood pores. You won't need a great amount of pressure; 1000-1200 psi is more than enough. A large pressure washer isn't necessary. You do not need to use wood brighteners or cleaning chemicals after sanding. The sanding should have removed all discoloration from the wood.

Use the widest spray nozzle, 40 Degree, and hold it 12 inches off the surface. Wash off the house as well. Inevitably sanding dust will have stuck to the house.

Deck Power Washing As The Main Means of Preparation

Power washing can be used as the only means of preparation if the deck is in good shape or if the traditional sanding isn't desired. You have two choices, power wash with a wood brightener chemical or without.

Deck power washing with wood cleaners and restorers can remove most deck stains, tannin streaks, rust stains and mold. These cleaners can't remove solid color deck stains or paint.

• Mix according to the manufactures directions into a 5-gallon bucket, ½ of a bucket at a time.
• Pre-moisten the deck using water only from the power washer. This will remove the surface dirt and allow the cleaner to soak into the wood.
• Apply with a stiff broom or deck cleaning brush. Scrub in the direction of the wood grain. Allow to remain on the surface for 5-10 minutes.
• Rinse using 1500-1800 psi and 25 Degree spray nozzle, 12 inches from the surface. Use the same sweeping motion already mentioned.
• Rinse the wood thoroughly and the surrounding landscaping. Use the lowest pressure setting to rinse all plants in the surrounding area.
• Allow the wood to fully dry before applying any new stain.

Deck power washing without cleaners is also possible. In order to achieve a satisfactory result you will need higher pressures plus the spray will have to be closer to the wood. Use 2000-2500 psi at 8-10 inches from the surface. A 25 or 15 Degree spray nozzle needs to be used to increase the cleaning power. Be careful, using the 15 Degree spray nozzle is difficult plus washing to close can cause some damage to the wood.

You can decrease the chances of causing damage by reducing the pressure and moving slower. Use the same sweeping motion during power washing to reduce damage to the wood.

Heavy washing without chemicals is usually used to remove peeling finishes prior to sanding. Repeat the washing if the surface is uneven in color or at least do a light sanding.

Now that the deck is ready for some color and protection, choose the best deck stain that you can afford and properly apply the deck stain for lasting results.