What's The Best Pressure Washer Setting When Cleaning A Wood Deck?

Pressure washing your deck is a great way to remove dirt, mold, and mildew to make it look almost new again. However, if you use the wrong setting on your washer, you might leave behind splinters or cause extensive damage. It's not the same as pressure washing your home, since materials react to water pressure differently.

Measured in PSI (pounds per square inch), your washer's pressure is a way to tell you how hard the water will hit your wooden deck. While higher PSI is tempting, it could end up marring the wood fibers. When cleaning a deck, your pressure washer should have a PSI setting between 1,500 and 2,500, but depending on the type of wood, it may need to be lower. 

Hardwood or composite decking can tolerate a moderate PSI level, but soft woods need a more gentle approach when cleaning. Starting too aggressively with high pressure is a mistake everyone makes when pressure washing, because they don't understand that more pressure doesn't necessarily mean a better clean. In fact, too much PSI can damage a surface.

Proper technique is another important part of pressure washing, and your choice of nozzle and how closely you hold it to the deck also matter. Aside from just looking at the top-rated pressure washer for your deck, you might also consider checking different types of pressure washers, such as electric vs. gas.

Softer woods such as pine or cedar should stay at 500 to 600 PSI, since they are more delicate and can splinter or leave streaks easily if blasted too hard. Excessive pressure can also ruin stains and composite finishes on your deck, so be cautious. If you know that your wooden deck is not made of cedar or pine, you can safely start around 1800 PSI and increase it slowly until you see that it cleans the surface. Denser hardwoods like teak are usually stronger, and can handle a decent level of pressure. If you're unsure about the setting, start low at 500 PSI in a small, hidden area before you wash in a higher-traffic spot.

When pressure washing your deck, you must first clear the deck completely. Remove furniture, plants, or other items and then sweep away the dirt and debris from the surface. You can pre-soak the deck with a cleaning solution, just be sure to use the right deck cleaner for your wood type. Use a 25-, 40-degree or a 60-degree fan tip nozzle, which spreads the water over a wider area instead of concentrating it. Always spray at an angle and avoid any 0-degree tips, since they can eat into the wood.

Holding your sprayer too close to the deck can also cause damage. Position the nozzle about 12 to 18 inches away when you spray. It also helps to continuously move it in smooth, sweeping motions as you clean – staying in one spot for too long may create marks. Pressure washers work best when you follow the direction of the wood grain. Let the wood dry for at least a day before applying any stain or sealer.