Here’s the bad news: Every deck should have an annual cleaning. Assuming they have been maintained regularly, most decks can be revived with just a deck cleaner. Some products, like Thompson’s Deck Wash ($33, 1 gal. covers 250 sq. ft.), you mix in a bucket and apply to the deck; others, like Simple Green ($20, 1 gal. covers 500 sq. ft.), come in containers with integral applicators that you hook up to a garden hose. Once on the deck, most still require a stiff-bristle brush and a lot of elbow grease to work the mixture into the wood.
Always wear eye protection and gloves when working with concentrated chemicals. You’ll also want to protect nearby plants. The level of plant protection depends on the type and concentration of the chemicals you choose. For weak solutions and “plant-friendly” cleaners, you may need to only mist the plants before and after using cleaning. Powerful deck restorers can burn leaves on contact; in that case you should cover nearby plants with plastic sheeting.
For tackling tough stains, use a pressure washer (about $70 a day), which is the best way to remove sun-damaged wood fibers and tackle scrub-resistant stains. Graf recommends using a fan-type nozzle instead of a pinpoint nozzle that can dig into the wood. For removing the mildew, Graf mixes his own cleaning solution (see “Choosing the Right Cleaner,” on the facing page), which he feeds into the intake hose on the washer.
Go over the deck with a stiff-bristle brush to work the cleaner into the wood fibers, and then rinse. The boards should be kept damp in order for the cleaning solution to work effectively. Allow the deck to dry thoroughly before staining.
Choosing the Right Cleaner
There are dozens of deck-cleaning products on the market. Most contain one of the following four chemicals as their main ingredient. Each is effective for different types of stains.
This chemical—chlorine bleach—is good for removing mildew but isn’t effective on dirt or other stains. So mix it with an ammonia-free detergent. Thoroughly rinse the deck after using this chemical because it can eat away at the wood, resulting in fuzzing and premature graying.
When mixed with water, this chemical forms hydrogen peroxide (an oxygen-based bleach) and sodium carbonate, which acts as a detergent. It is good for removing dirt, mildew and weathered wood.
This is effective in removing iron stains and the brown-black tannins that frequently occur with cedar and redwood decks. This acid is commonly found in deck brighteners. Oxalic acid isn’t effective against mildew, so you may want to use it after cleaning the deck with a bleach-based cleaner.
Also known as lye, this is the key ingredient in most finish lifters or removers. Don’t leave it on too long, or it can eat away at the wood.
Be very careful when working with any of these chemicals, especially when they’re in their most concentrated (premixed) form. Wear the proper safety equipment and follow the manufacturer’s directions to the letter. Rinse the surface thoroughly and allow it to dry before refinishing.
Here’s a deck cleaner you can make yourself. Recommended by the U.S. Department of Agriculture Forest Products Laboratory, it’s good for mildew and dirt.
1 qt. sodium hypochlorite solution (household bleach)
⅓ cup powdered laundry detergent
3 qts. warm water
In a 5-gal. plastic bucket, add the bleach and detergent to the water, then brush the cleaner onto the deck. Rinse thoroughly before applying a finish.
Caution: Do not use a detergent that contains ammonia. Ammonia and bleach react to form a poisonous gas. Step 3: Applying the Stain
Once all of the repairs have been made and the deck is clean, it’s time to apply a protective finish. Clear finishes and transparent stains are fine for new wood, but for older decks, Starling recommends using a semitransparent stain.
”The grain still shows through, but the pigment gives the old wood a clean, uniform color and helps the new wood blend in,” he says. The pigment also provides extra protection from the damaging effects of the sun and will last longer than clear finishes. Unlike paint, stain is absorbed by the wood and does not form a film on its surface, so it will not peel or chip.
Starling uses a sprayer and 2-in. brush to apply the stain. “Spraying is fast, and puts more stain on the wood than rolling or brushing,” Starling says. Most painters and homeowners are better off spraying on a generous coat of stain and then following up with a roller or brush to spread out puddles and work the finish into the wood. Starling, however, uses a modified technique. “Rollers push the stain off the wood and down the cracks,” he says. “I don’t get paid to paint dirt beneath the deck.” Starling sprays on a light coat, most of which is quickly absorbed into the wood. He uses the brush to remove puddles. “If the stain’s too thick, it dries blotchy,” he explains. Starling recycles the excess stain for use on exposed end grain.
Starling recommends starting at an inside corner and working out, applying the stain parallel to the deck boards. To avoid staining the nearby brick, he uses a small piece of cardboard as a spray shield; the brush provides even more control around deck railings and posts.
This 700-sq.-ft. deck required about 5 gal. of stain — almost twice as much as the estimates indicated on the can. Explains Starling, “Old wood can get thirsty. On some decks, I’ll need to apply two or three coats of stain in order to get a uniform finish.”
Subsequent coats should be applied while the first coat is still wet or they will not be absorbed into the wood. Stain won’t peel, but it can wear away, especially in high-traffic areas. Starling recommends applying a fresh coat every other year. A clear water repellent can be applied between stainings for extra protection.
Step 4: Redoing a Railing
Because the original railing on their deck was in such bad shape, the Johnsons decided to replace it with a maintenance-free railing system. They chose Fiberon, a vinyl-coated wood-plastic composite. It’s available in premade panels or as kits. The Johnsons liked the contrast the white railing offered.
Tip: After cutting the end post flush with the deck using a reciprocating saw, remove the old railing in sections.
For an existing deck or concrete slab, Fiberon makes a surface-mount bracket, as shown below. For new decks, the manufacturer recommends installing the posts before the decking and using metal brackets that attach to the joists. To conceal any minor gaps where the balusters meet the bottom rail, Graf recommends using a mildew-resistant acrylic caulk.
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