Before you begin power washing your deck, you will need to make some decisions about how you plan to go about washing. Power washing is fun, but it also requires some strength and careful attention to how the washing is going.
Some decks really need detergent to help clean the deck. If you do lots of projects on your deck or have more than five years’ worth of grime build-up, then a detergent will be necessary. Detergents also help for decks that are green from mold and algae. If you choose to use a detergent, pick the least abrasive one you can find to protect yourself from inhaling more detergent, the environment, and your deck.
Put detergent onto the deck according to the manufacturer’s suggestion. Too much detergent won’t get your deck cleaner; it will leave residue even after power-washing. Leave the detergent on for a max of 15 minutes to make sure that it doesn’t have time to dry.
Small power washers are around 1200 psi, or pounds per square inch. This low setting will work, but you will spend more time going back and forth on the deck. Instead consider getting something stronger. Around 1500 psi should do the trick for small decks, though really dirty ones can use up to 2400 psi. Anything stronger than that can begin to cut into the wood and cause structural problems.
Some nozzles provide pinpoint position, which can be useful if you are power-washing something with a lot of detail. For most decks, however, you will want a wider spray area. Something around 15 inches works well enough that you can control the nozzle and get a good spray.
When you get started, you want to begin on one side of the deck. Begin by spraying in a line, rather than haphazardly. Go over each section at least twice, using a grid-like pattern. Then allow the deck a few minutes to begin to dry. As the deck is drying, any shiny or dirty spots need a bit more work on them.
For an average-sized deck, power-washing it shouldn’t take more than an hour. Be prepared, though, that you should not power wash a deck that is already wet, so don’t power wash immediately after a rain. Also keep in mind that the deck needs to dry for 24 to 48 hours after the washing is done, which means that you should plan to power wash on a Thursday or Friday if you are painting or staining over the weekend.
Power washing a deck requires hard work, but the results are quick. You will be able to see the benefits of your work as soon as you are done, which most people enjoy. Just keep in mind that power washing machines are powerful and can get away from you quickly if you are not careful. Keep the machine on level ground and pay close attention to it the entire time you are working.