Envirotek Restoration, Inc. Industry Info

Using the wrong water pressure can permanently damage your deck.

“If you’re cleaning a deck using a water pressure treatment, you should be concerned about the amount of pressure you use,” says Sammy Alfadel, owner of Envirotek Restoration, Inc. For redwood decks—a soft wood that’s easily damaged— he says the pressure shouldn’t exceed 1,500 pounds per square inch. “A lot of people try to do it themselves and end up making grooves into the wood grain.”

Mr. Alfadel says it’s also important to use a proper cleaner to dissolve dirt and old stains from the wood. In fact, he says, the cleaner alone will accomplish 80 percent of your deck cleaning.

Lightly sanding the wood will open the grain and permit better penetration of the stain. Mr. Alfadel recommends using a high-quality product that protects the wood from the inside rather than simply sitting atop it.

Depending on the type of wood in your deck and its exposure to the elements, its cleaning schedule can range from one to three years. In between, however, you should consider applying a hard “scrub” with a broom. Mr. Alfadel says that’s a good idea, but he warns that too much pressure can remove the wood’s protective outer layer of oil. The best way to maintain a deck between cleanings, he says, is to simply hose it down periodically and, if possible, use a blower to remove dust.