Moisture, sunlight and even air pollution can take a toll on wood decking. If you want a deck that looks like new again, you have two options -- you can replace the deck completely, or you can attempt to restore it. Replacing decks is expensive and time consuming. Restoring wood decks is much more frugal. It takes time, patience and effort to do this, but you may be very surprised how an old, tired-looking deck can be restored to look almost as good as the day it was built.
Put on protective gear, which should include gloves and safety glasses. Pour a bit of deck cleaner directly onto the deck, unless it must be mixed with water (as many kinds do). If the latter is the case, mix it with water in a clean bucket and then pour it onto the deck.
Work the cleaner into the deck using a sponge mop. Work section by section until the whole deck is covered with the cleaner. Scrub it once more with the mop before continuing.
Rinse off the entire deck with a pressure washer. Make sure the pressure is not set too high, and hold the sprayer several feet from the surface to prevent damage to the wood. Use back and forth sweeping motions, going with the grain -- never direct the spray on an area for more than a half a second.
Let the deck dry completely. This can take as long as three days, and will usually take at least one day. Assess the entire deck for uneven or broken planks. Replace any, if necessary. Also at this time, check for loose or missing nails. Replace the nails, and hammer in any loose ones.
Choose an area of railing to stain first. Place a dust sheet, paper, or cardboard down below it to protect the deck planks from drips. Apply stain to the railing with paint brush, a section (approximately 1 metre) at a time.
Pour small amount of deck stain on the deck floor. Work this in with a paint roller. Move to the next section and continue until the entire deck is stained.
Some deck cleaners work best if you wait between applying and rinsing -- check the label.
The deck may become very slippery during cleaning.
If the deck still has traces of the old finish on it, you may need to scrape this off (you can use a chemical stripper to loosen it first) before applying a new finish. This is especially important if the old finish is a different type than the new one you plan to use.
Cleaners and stains can be harmful to plants. If you have any near the deck, make sure to cover them while working.