It depends. Composite decks from brands such as TimberTech and Trex often resist deep staining and clean nicely with a light scrub, followed by a rinse with a garden hose. But if that isn’t enough, check the terms of the warranty to make sure pressure-washing won’t void it.
Decks made from South American hardwoods, such as ipe, cumaru, and tigerwood, will hold up to a power wash just fine. Those made of pressure-treated wood—typically Southern yellow pine, a soft wood— are generally okay, too, assuming you don’t hold the nozzle too close.
Check your owner’s manual to confirm which nozzle and setting the manufacturer recommends for decking, and how far away from the surface it should be held. Generally speaking, it’s best to start with a low-pressure nozzle on an inconspicuous spot to make sure the spray is not etching or marking the wood. Once you find the right nozzle, setting, and distance, work along the length of the board, following the grain of the wood.
Gas or electric pressure washer? This is a relatively light job, so a corded electric washer, like the one below, is all you need.
Recommended pressure: 800 to 1,000 psi
