How to Pressure Wash a Deck?

Wooden decks are a great feature of many gardens, houses, and commercial areas. They’re attractive and classy, but take a little more maintenance than certain other outdoor features. If not properly maintained, the wood can weather to a high level, growing mold or moss and eventually rotting away. As such, it’s important to look after your wooden deck with care. An important part of maintaining your deck in good condition is cleaning it, both on a regular basis and before you apply any protective coatings to the wood. The best way to do this is to pressure wash the deck with a powered pressure washer, as well as using mold removers.

Here at Best of Machinery, we’ve put together a list of handy tips for pressure washing your deck with a power washer to get the deepest clean possible on the wood without risking any damage to your wooden deck. It’s important to be careful when you pressure wash a deck, though, as excessive power from your pressure washer can etch the wood and splinter the wood fibers that make up your decking.

Related review; Karcher Gas Pressure Washer

Preparing to Pressure Wash a Deck

It’s important that you choose the correct setting when you set out to wash a deck. Too much pressure or too narrow a tip and you can severely damage your deck, breaking the wood with the force of the water, while too little pressure will fail to clean the deck properly.

As a general rule, here at Best of Machinery, we would recommend using approximately 500 psi to 600 psi for soft woods such as pine or cedar, with higher pressures for harder woods, but we would advise never using pressures higher than 1200 psi for even the hardest of woods. Higher pressures are designed for harder surfaces such as concrete and can cause severe damage to wooden surfaces.

Use a spray nozzle with a 40 to 60 degree spread setting for pressure washing a deck. Narrower spray tip nozzle spreads can cut into wooden decks and damage them, even if you’re using a lower water pressure. It’s also worth testing your spray settings on a piece of scrap wood or an inconspicuous corner of your deck if you’re not confident; if you’re not certain your settings are safe for the wood you’re spraying, it’s always better to test it on a less important piece of wood than it is to dive in and start spraying your main wood decking area!

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Pressure Washing Technique for Wooden Decks

Technique is an important thing to consider when you pressure wash a deck. Keeping your pressure washing technique constant and correct can make a massive difference to the efficiency of the cleaning process, and attempting to pressure wash a deck with poor technique can cause damage with the wood. Following our guidelines will help you to clean your wooden deck effectively and safely without risking damage to the deck.

Start with your power pressure washer set to 500 to 600 psi, and test it out on an inconspicuous area of the deck before you start properly. If this pressure doesn’t seem to be making any difference to the dirt, slowly and gradually increase the pressure until you can see a difference to the cleanliness of the wood. Make sure you increase the pressure as slowly as possible; jumping up to a higher pressure can lead to damaging the wood, and changing the pressure as slowly as possible can help to avoid that risk.

Hold the spray wand about 24 inches (2 feet) above the deck before engaging the trigger, and then gradually lower it to about 12 inches above the wooden deck. Always clean with a smooth, lateral sweeping motion, holding the spray wand about 12 inches from the surface for the smoothest and most effective clean with minimal risk to the wood.

Keeping the nozzle a constant distance from the surface you’re trying to wash will keep the pressure of the water impacting against the wood at a consistent level, cleaning the surface as evenly as possible. Clean from the house side of the deck outwards, blasting the dirt away from your house rather than towards it. This will keep your walls clean and push the dirt away from clean areas and into your garden, keeping the entire area looking clean and fresh.

Sanding After Pressure Washing a Deck

When wood gets wet, the fibers swell up and make the surface rougher than when it’s dry. Even when the wood dries out, this uneven surface won’t always return to a smooth finish on its own, which can be a particular problem on areas such as handrails, as it increases the risk of splinters, meaning that it can be worth sanding your wooden deck after you’ve pressure washed it in order to smooth off the wooden surface as much as possible.

Leave the deck to dry completely before sanding, as wet wood is softer than dry wood, and can easily be torn up by sandpaper if you’re not careful. Coarse sandpaper is the best option for sanding a deck, as fine sandpaper can leave a surface that’s difficult to stain or seal afterward. We would recommend using a sandpaper of about 70 grit – no finer than 100 grit, and no coarser than 50 grit; 60 to 80 are good numbers to look for.

Once you’ve sanded any rough areas of the wood back to smoothness, you can seal or varnish your wooden deck like any other piece of wooden garden furniture, helping to protect your surface effectively and keeping you safe and splinter-free!

If you don’t yet have a pressure washer, we’ve taken a look at the top-selling options. This Simpson pressure washer does come up pretty well!

Conclusion

Pressure washing a deck doesn’t have to be difficult; if you follow our recommendations above, you can quickly and easily clean a wooden deck without risking damage to the wood, keeping your garden furniture looking clean, fresh, and new with minimal effort. Keep an eye on your pressure, and you’ll be confidently cleaning your wooden deck in no time at all!