Hit The Deck

With the weather warming up, plenty of us are probably looking forward to spending another summer on the deck.

But consider all that your poor deck has been through since you folded up the lounge chairs last fall.

Rain and snow soak the wood and cause it to swell and warp, leading to cracks when it dries out. The moisture breeds mold and mildew that make wood rot.

And the sun isn’t much kinder. Its ultraviolet rays break down lignin, a compound that holds together the cellulose fibers in the wood. The result: a gray, dingy-looking deck.

Despite spending hundreds or even thousands of dollars building their deck, many people don’t put much money or time into maintaining it.

“Most people don’t do anything with their decks, even when they’re new,” says Lonnie Hubbard of Hubbard Construction in Spokane, which specializes in decks.

“I’ve seen a lot of people just let them go and turn gray. They lose their natural oils and they start coming apart.”

So this year, make sure to add your deck to your spring cleaning list - starting with a good scrubbing.

There are several deck-cleaning products on the market that can make weathered wood look almost like new. Consumer Reports magazine recommends a mixture of one quart bleach, three quarts water and three ounces Red Devil TSP Phosphate-Free Cleaner.

“It’s all about the same stuff,” Hubbard says. “Any of them will work. Just scrub it on with a brush and hose it off.”

It’s not quite that simple, though. Deck cleaning also means removing debris - dirt, leaves, pine needles - that gets stuck in the spaces between boards. That traps moisture and hastens wood rot.

A hard spray of water from a hose can wash out much of the residue, but you’ll probably spend some time on your knees with a putty knife, too.

While you’re down there, look for nails or screws that have worked their way out of the wood and sink them back in or replace them. (If they need to be replaced, and you’re using the same holes, make sure to use nails or screws that are a little longer than the originals so they’ll hold.)

Rotting wood also needs to be replaced before the decay spreads. New decking can be “weathered” to match the existing boards by scrubbing with a solution of 1 cup baking soda in 1 gallon warm water, according to Sunset magazine.

But it’s the rotting you can’t see that’s the real problem, says Hubbard. Moisture seeps through the nail or screw holes and collects where the planks meet the joists.

“In between the boards and the joists is where it rots, and you don’t see that until you pull off the old decking,” he says. “A lot of people think their decking is what needs replacing, but once the decking comes off, the joists are rotten.”

If that happens, remove the rotted portion of the joist with a hammer and chisel, and coat the rest of it well with a sealer-preservative. Then nail a new “sister” joist, also treated, alongside the old one for support.

Once the deck is clean and structurally sound, it needs to be treated - top and bottom, if possible - to help prevent future water damage.

Sunset advises working on a cool, cloudy day - or at least early in the morning or late in the afternoon, out of direct sunlight - so the treatment will soak into the wood instead of evaporating.

Just be sure the deck has dried thoroughly from its initial washing, Hubbard says, preferably for four or five days. “Otherwise, the moisture, when it comes back out, will push out the stain,” he says.

What treatment to use is a subject of some debate. While clear treatments are popular with people who want to preserve the appearance of redwood or cedar decking, they don’t offer as much protection as coatings with some pigment in them.

In 1996, Consumer Reports launched what was intended as a five-year study of various deck treatments. But after just 20 months, nearly half were doing so poorly in protecting wood from the elements that they were removed from the test; most of those were clear treatments.

The top-scoring clear treatment in a report published in June 1998 was DAP Woodlife Premium Wood Preservative, at about $13 per gallon. The best-performing semitransparent treatment - which is dark enough to mask the wood’s grain - was Cabot Decking Stain ($24 per gallon).

Hubbard recommends United Paint’s In/Wood ($18 per gallon) and Superdeck ($23 per gallon at Spokane Cedar Products), both of which come in various colors. While In/Wood needs to be applied every year, he says, you could probably go every other year with Superdeck.

If even that sounds like too much work, Hubbard has another suggestion: putting some sort of roof over your deck. That might reduce the need for treatment to every four or five years, he says.

“Especially if your deck is on the hot side of your house,” Hubbard says, “if you put a cover over it, you’re keeping the sun out and you’re protecting your deck.”

This sidebar appeared with the story: HOME IMPROVEMENT On the boards Some spring tips for keeping your deck in tip-top shape: * Scrub with a deck-cleaning compound to restore its appearance. * Remove debris that collects between boards, which traps moisture and promotes wood rot. * Replace or reinforce rotting deck planks and joists. * Repair or replace loose or rusting nails, screws and other hardware. * Coat with a water-resistant treatment; those with more pigment offer more protection and may not need to be applied as often.