This Pressure Washing Mistake Can Ruin Your Deck Fast

Pressure washing is the most efficient and effective way of cleaning your deck. But, as with any task that requires a pressure washer, it’s also risky. Use the wrong nozzle or technique and you can easily end up stripping off sealants and stain or even splintering the wood. Following strict guidelines when pressure washing your deck is key to cleaning it without damaging it. 

Related: This Common Pressure Washing Mistake Leaves Streaks and Spots

Using Too Much Pressure

When a deck is looking mildewed, dull and grimy, your first instinct might be to hit it hard with high pressure water to blast away all that build-up. That’s a fatal error. 

Pressure washing your deck using the wrong tip is one of the most common mistakes when cleaning a deck. It’s particularly destructive to softwoods like pine, cedar, and redwood, leaving behind permanent scars. Use a nozzle with too narrow a stream, such as a 0 degree or 15 degree tip, and you can easily damage it: 

• Furring: Too much water pressure can damage the surface of the deck, causing the wood grains to raise and appear fuzzy after washing. 

• Tiger striping: Using too narrow a tip can also create a striped pattern on the decking, which is when the pressure washer leaves streaks from uneven washing. 

• Scoring: If you’re washing a composite deck, high pressure water can score the surface, permanently damaging the decking and voiding its warranty. 

• Stripping: A pressure washer can easily strip sealant off a deck if you’re not careful. 

Using the Wrong Cleaner 

Using chemical means as opposed to physical means to remove dirt, mildew, and algae, is a safer and more effective way of cleaning your deck. Purchase a cleaner specifically designed for cleaning decks. Oxygen-based cleaners, such as Restore-A-Deck Cleaner and Simple Green Oxy Solve Deck and Fence Cleaner which are formulated to break down dirt, mildew, and stains that are common on decks. 

Related: Why Pressure Washers Cause Thousands of Injuries Every Year

Use a Lower Pressure Nozzle

Rather than go with a high pressure nozzle, use a broader 25 degree or 40-degree nozzle. These nozzles produce a wider fan that’s safer for soft woods and composite decks while also allowing you to hit a wider area of deck as you’re cleaning so you can get a more consistent finish. 

Use Lower Pressure Settings

Keep the pressure setting around 1500 PSI, which is safe for decks. Never exceed 2,000 PSI, which will damage the wood. 

The Right Distance

When washing your deck, maintain a distance of at least 12 inches between the wand tip and the deck surface. This will ensure that you don’t focus pressure on too small an area of the deck, which can damage it. 

Scrub if Needed

Resist the urge to move the wand closer to the deck or load a more aggressive nozzle if there are stains that you can’t remove. Scrub the stain with a stiff bristled brush by hand instead and then rinse with your pressure washer at a safe distance using the correct nozzle. 

Additional Deck Pressure Washing Tips

• Avoid cleaning your deck in direct sunlight, otherwise the deck cleaner may dry before you have a  chance to rinse it
• Work in small sections so you can rinse the deck cleaner before it dries
• Wait for the deck to dry completely before applying a sealant, otherwise you’ll trap moisture inside the wood, which can lead to mold and rot.