A scrub brush will get your deck clean, but a pressure washer can do the job faster and more effectively. Just be sure to follow the manufacturer’s instructions to avoid damaging the wood.
Before you begin washing, remove outdoor furniture and cover any plants or shrubs that could be harmed by the soapy water. Also cover any exterior lights or vents.
Use a Cleaning Solution
Before firing up the power washer, prepare your deck with a cleaning solution, if necessary. For mild stains and dirt, try using a deck detergent or non-toxic oxygen bleach with a stiff brush before rinsing. Always read the product instructions carefully, use rubber gloves and eye protection, and follow any safety recommendations for use.
For stubborn stains, use a solution that contains oxalic acid to break apart the molecules of the stain or mold and mildew, without harming the wood. This is an uncomplicated mixture of liquid dish soap and warm water, readily available in most households, and suitable for all types of wood decking materials.
When you’re ready to start, switch to the widest spray nozzle on your pressure washer (not counting the one used for soap). Start about two feet away from the deck surface and move closer only if needed; getting too close could damage or etch the wood fibers. Sweep in a wide pattern and overlap your spray strokes to conceal the starts and stops of your sweep.
Test the Pressure
When using a pressure washer, it’s important to test the water pressure in an inconspicuous spot on your deck before spraying. Commercial high-pressure cleaners can reach up to 5,000 psi, and too much pressure can damage the wood, creating splinters and cracks.
A pressure washer with a low-pressure soap nozzle can easily clean off dirt, mildew and other contaminants from most decks. If your deck is especially dirty or overdue for a cleaning, consider pre-treating it with a wood brightener or stripper to lift up stains and loosen debris.
During cleaning, keep the spray nozzle at least two feet away from the surface of your deck to prevent damage. It’s also helpful to keep the nozzle moving during washing to avoid applying pressure to one area for too long, which can lead to warping and splitting in the wood. Remember to protect shrubs, gardens and air conditioning units with a drop cloth or plastic sheeting.
Adjust the Nozzle
Pressure washers are invaluable tools for reviving wood decks and washing away debris, dirt, and grime. But if you mishandle them, you can blast a deck to smithereens—or risk serious bodily injury.
To avoid damage to your deck, start by testing the current pressure output on a small section of the surface. This will help you determine how close you can safely get to the wood without causing damage.
Once you know how much pressure the wood can handle, you’ll be able to use the nozzle to remove stubborn dirt and mold. We recommend using a sweeping motion while always moving the nozzle a few feet away from the wood. You can move it closer as needed, but don’t get too close or you could cause splintering.
Start in the Right Place
Before you start cleaning your deck with a pressure washer, make sure you have the right equipment for the job. If you’re not used to using one, beware of kickback, and consider buying or renting a safe extension wand for high areas, or hiring a professional.
If you’re using a cleaning solution that requires mixing, do so according to the manufacturer’s instructions. If not, start by applying the cleaner with the black soap-dispensing nozzle on your pressure washer. A good practice is to apply the cleaner in long, sweeping strokes, overlapping each one. This will prevent lap marks on the wood.
When you begin to wash your deck, keep the nozzle at least 12 inches away from the surface of the board and move closer gradually as needed. If you get too close, you could damage the planks with too much pressure. The nozzle produces a fan-shaped stream of water, and you can control the direction by moving the tip in and out.clean deck with pressure washer
