Deck Washing That Leaves the Wood Ready for Stain

Deck wood is softer than it looks. Pressure treated pine and cedar both have soft wood between the harder growth rings, and a tight spray at close range eats the soft part first. The deck comes out clean and then dries with a fuzzy, raised grain, splinters standing up along every board, and marks wherever the wand paused. That is called furring, and the only fix is sanding. The better way is to let a deck cleaner loosen the gray, the mildew and the dirt, then rinse with a wide fan held back from the boards. The gray on an old deck is the top layer of wood fibers breaking down in the sun, and the cleaner lifts those dead fibers so the rinse can carry them off. Then a brightener goes on. It neutralizes the cleaner, which tends to darken the wood, brings the color back, and leaves the boards ready to take stain evenly.

Composite decking has a different problem. It won't rot or splinter, but the texture molded into the boards holds pollen, dirt and the dark spots of mold, especially on a shady deck under trees or on the north side of the house. Most composite makers limit the pressure you can put on their boards and rule out a turbo tip entirely, because it can scar the cap layer and put the warranty at risk. So composite gets a cleaner made for it, a soft brush where the spots have taken hold, and a low pressure rinse. Railings, balusters and the underside of the handrail get the same attention as the floor, since that is where the green builds up first. Before any of it, we cover the lights and outlets on the deck, move the grill and the furniture, and soak the plants below the edge so the runoff doesn't burn them.

What the visit covers

• Clear furniture, grills and planters off the deck before washing
• Cover deck lights, outlets and any fixture on the house wall
• Soak the plants and beds below the deck edge first
• Apply a deck cleaner and let it loosen the gray and the mildew
• Rinse with a wide fan held well back from the boards
• Brush composite by hand where mold spots have set in
• Neutralize and brighten wood so it takes stain evenly
• Wash both faces of the fence, plus the posts, caps and rails
• Check moisture before any stain or paint is scheduled
• Flag soft boards, popped nails and loose posts we find

Fences, drying time and getting to the stain

Fences get washed on both sides wherever we can reach both sides, because the side facing the neighbor is usually the shady one and the one that grows the most. Vinyl fencing along a property line picks up green algae on its north face the same way vinyl siding does, and it cleans up the same way, with a solution and a gentle rinse. Wood fence boards are thinner than deck boards and dry faster, but they fur just as easily, so they get the same low pressure treatment. Posts and caps get a look while we're there. A post that rocks when you push on it, or a cap that has split and is letting water into the end grain, is worth knowing about before you pay to stain the whole run.

Stain needs dry wood, and that means dry through the board as well as on top. After a wash, most decks need about two days of dry weather before they're ready, longer in shade or when the air is humid, and we check with a moisture meter instead of guessing by touch. If you're having the deck stained or painted, the wash is the first step of that job, and our painters take it from there once the readings are right. That keeps the whole thing on one schedule and one scope. If you only want the wash, you get a clean deck and an honest read on the old finish, including whether the last stain is peeling badly enough that it has to be stripped before anything new goes on.