Here are some tips for cleaning a Wood, Composite or Cedar/Redwood deck:
Using that Power Sprayer – A power sprayer is a huge time saver when cleaning a deck; but before you hook it up and dial in a laser beam of water consider that you may do more harm than good. Using a narrow, high-pressure stream of water can wash off paint, and even gouge the wood so badly you couldn’t even hide it with a new coat of paint. It can also ruin the surface integrity of composite materials. By breaking the surface you are inviting mildew and grime.
It is best to hold the nozzle about 2 feet above the deck surface while swinging the nozzle back and forth like a pendulum. You may not be able to remove every stain with the power sprayer – and that is ok! Leave them to be finished later with a deck cleansing solution and a small brush.
Cleaning a Wood Deck – Make sure you first get all the needles or other debris out from between the deck planks. You don‘t want to be sealing in those needles and the moisture that can come along with them. You can usually just use a hose or power washer to clean out hard to reach places. For what the water doesn’t get, a putty knife or other thin blade is usually your best bet.
To clean the wood there are multiple deck cleaners out there. Always read carefully to make sure you have the correct cleaner. Don’t forget to cover all that stuff you have under the deck, like plants and your lawn furniture.
Cleaning a Composite Deck – Despite their well-deserved reputation for being low-maintenance, composite decks are not completely maintenance free. The good news is dirt and debris usually wash away easily with a garden hose.
However, a deck cleaner will probably be needed to get rid of stains and heavy mildew. If you’re not sure where to start, you can contact the manufacturer of the decking material. Usually their websites provide cleaning tips and advise you as to which cleaners are best. When using a deck cleaner, the usual procedure is to spray it on (you can use a cheap hand pumped sprayer), let it sit for about 20 minutes, then wash it off with a garden hose.
It is not recommended to sand composite decks to remove a tough spot or stain.
Cleaning a Cedar Or Redwood Deck – Cleaning a cedar or redwood deck is similar to cleaning a composite deck in many respects. Cedar and redwood, and most treated woods, are decay resistant, and also have less of a tendency to harbor mildew, although in areas receiving heavy moisture, mildew can still be a problem.
Cedar is a soft wood and could too easily be damaged if you attempt to power wash it. There are specific cleaning solutions in stores for cedar decks. Consider applying a brightener after everything has dried to help restore the natural wood look.