A timber deck is hard-wearing and, if properly treated, will keep its appearance for a long period. To keep your deck looking its best, though, you'll want to clean it periodically. Most decks only need a regular cleaning two or three times a year. Clean your deck at the beginning of summer, when it's likely to see a lot of use, and again as winter starts.
What you'll need
Depending on the condition of your deck, you can clean it in one of two ways. A stiff brush and soapy water will deal with light buildup of dirt and algae. If your deck needs more intense cleaning, you may want to use a power washer to clear away the buildup. Either way, you'll also need a broom and possibly some drop cloths.
Clear the area
Before cleaning, remove any outdoor furniture from your deck. If you have a balcony-style deck with an area in use below it, make sure to put down drop cloths or a tarp on the lower level. Sweep the area clear of leaves and other debris before cleaning it. Depending on the state of your deck, this may be all that's required.
Clean the surface
Use a stiff brush and soapy water to scrub the surface of the deck evenly; you can buy special cleaning solutions for timber or use a solution of mild cleaner such as laundry detergent. Apply the solution evenly to the deck, focusing your attention on areas of heavy buildup discolouration.
This can be a time-consuming process for larger decks; if hand-scrubbing would take too long, use a power washer to spray the deck, using a wide setting and keeping the nozzle at an even height. Test the power washer on an unobtrusive area of decking first to make sure that you're happy with the result. When power spraying, try to work with long, even motions to keep the overall appearance of the sprayed timber consistent.
Rinse any remaining suds and any loosened algae or dirt off the deck with a garden hose. Let the timber decking dry before you put any furniture back in place. If you notice that exposure to the sun is causing variable fading of the deck, it may be time to apply a new coat of sealant or reposition furniture or awnings. Apply the coat evenly and let it dry before putting replacing your furniture. Drying times can vary, so follow the instructions on your sealant carefully.