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Introduction to Pressure Washing Your Wood Deck

By: Trevor Ross

When the time comes to breathe new life into your wood deck, especially before refinishing, simply scrubbing with a chemical deck brightener might not penetrate deeply enough to cleanse thoroughly. Enter the pressure washer—a powerful tool that, when used correctly, can remove built-up grime, mildew, and algae, restoring your deck to its former glory. However, a pressure washer's strength, which can etch brick or strip paint from siding, demands respect and careful handling to avoid damaging the wood of your deck.

The pressure washer operates by propelling water at high speeds, powerful enough to tackle tough stains and years of dirt accumulation without the need for harsh chemicals. Yet, this same power can be detrimental, gouging wood or causing splinters if not handled with the appropriate technique. It’s crucial, therefore, to familiarize yourself with the pressure washer’s settings and to test it on a less visible area of your deck to ensure the chosen pressure does not harm the wood.

Choosing the Right Pressure Washer

Not all pressure washers are created equal, and selecting the right one for your deck-cleaning project is pivotal. Pressure washers are categorized by the strength of their water jet, measured in pounds per square inch (PSI). For wood decks, a pressure washer with 1200 to 1500 PSI provides enough force to clean the surface without risking damage to the wood.

In addition to pressure, the volume of water the machine delivers, measured in gallons per minute (GPM), plays a crucial role in the cleaning process. A higher GPM can rinse debris away more quickly, enhancing efficiency. Electric pressure washers often offer a balance of pressure and volume suitable for deck cleaning, making them a preferred choice for homeowners.

When in doubt, consider renting a pressure washer from a local home improvement store or tool rental outlet. This not only allows you to get the feel of the equipment but also lets you select the most appropriate model for your needs without committing to a purchase. Rental costs vary but typically range from $40 to $100 per day, making it a cost-effective option for a one-time project.

Preparing Your Deck for Pressure Washing

Before firing up the pressure washer, prepare your deck to ensure the cleaning process is both safe and effective. Remove all furniture, grills, and decorations from the deck area. Check the deck for any loose boards or protruding nails that might pose a hazard or could be damaged by the pressure washing process. Secure any loose elements to prevent damage.

Sweep the deck thoroughly to remove loose debris, leaves, and dirt. This step ensures the pressure washer can directly target the stains and build-up on the wood, rather than merely displacing loose surface material. Cover any nearby plants or shrubs with plastic sheeting to protect them from the powerful water spray and any cleaning solutions you may use.

The Pressure Washing Process

Start by selecting a nozzle or tip that delivers a wide spray pattern to distribute the water pressure over a broader area, reducing the risk of damaging the wood. A tip with a 40 to 60-degree angle is typically ideal for deck cleaning. Begin washing from a corner, working in sections, and keep the nozzle moving to avoid concentrating the water jet on one spot for too long.

Maintain a consistent distance between the nozzle and the deck surface—usually 12 to 18 inches—to ensure even cleaning and prevent gouging. Gradually adjust the pressure and distance as needed, based on the wood's response to the cleaning. Overlap each pass slightly to ensure no spots are missed, and periodically rinse away loosened dirt and debris to assess your progress.

After Pressure Washing

Once the deck is evenly cleaned, allow it to dry completely, which can take 24 to 48 hours, depending on weather conditions. Inspect the wood for any areas that might need additional cleaning or sanding, particularly if the pressure washing raised the grain of the wood or left rough spots.

Following a thorough drying period, your deck will be ready for refinishing. This can include staining or sealing, depending on your preference and the deck's needs. Applying a protective finish not only enhances the wood's appearance but also extends its lifespan by protecting it against moisture, UV rays, and further dirt accumulation.

Three Key Mistakes to Avoid When Pressure Washing Your Wood Deck

Pressure washing your wood deck can transform it from a grimy, aged surface to a refreshed, inviting outdoor space. However, improper use of a pressure washer can lead to damaged wood, an unsafe deck, and a host of other issues that may negate all your hard work. Here are three critical mistakes to avoid ensuring your pressure washing project enhances your deck without causing harm:

1. Using Excessive Pressure

The allure of power washing lies in its ability to clean surfaces with forceful water jets. Yet, this strength is a double-edged sword when applied to the relatively soft surface of a wood deck. Using too high a pressure setting can gouge the wood, creating splinters and an uneven surface that’s more susceptible to water damage and decay. Stick to a pressure range of 1200 to 1500 PSI for most wood decks, and always start with the lowest setting, gradually increasing pressure only as needed.

2. Holding the Nozzle Too Close to the Deck Surface

Distance matters when pressure washing. Holding the nozzle too close to the wood can concentrate the water jet's force onto a small area, leading to etching or stripping away of the wood surface. This can create uneven areas or divots that mar the deck's appearance and function. A good rule of thumb is to keep the nozzle about 12 to 18 inches away from the deck surface, moving closer only if necessary and always keeping the nozzle moving to avoid focusing the pressure on one spot for too long.

3. Ignoring the Deck's Condition

Before beginning the pressure washing process, thoroughly inspect your deck for any signs of damage, such as loose boards, protruding nails, or rot. Pressure washing over these areas without addressing the underlying issues can exacerbate problems, leading to further damage or even making the deck unsafe. Make necessary repairs to ensure your deck is in good condition before you start washing. Additionally, avoid pressure washing if your deck is made of softwood or is already in a fragile state unless you’re prepared to take on extensive restoration work afterward.

By avoiding these common mistakes, you can ensure that pressure washing your wood deck is a safe, effective way to restore its beauty without causing unnecessary damage. Remember, the goal of pressure washing is not just to clean but to do so in a way that preserves the integrity and extends the life of your deck. Take the time to prepare properly, use the equipment correctly, and treat your deck with the care it deserves to enjoy a beautiful, functional outdoor space for years to come.


Pressure washing your wood deck is a powerful method to restore its appearance and prepare it for refinishing. By choosing the right equipment, preparing the area, and following a careful cleaning process, you can effectively remove years of dirt and grime without damaging the wood. Remember, the key to successful pressure washing lies in understanding and respecting the power of the tool, ensuring a rejuvenated deck that looks as good as new.

By following these detailed steps, homeowners can confidently tackle deck cleaning, ensuring a thorough and safe process that sets the stage for a beautiful, refinished deck ready to enjoy throughout the seasons.

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