Lumber and building materials: treating decks right


Wooden decks are vulnerable to ultraviolet radiation, damaging them and turning wood varnish gray. Treated decks must be refinished every other year and given a thorough cleaning annually. The darker the stain, the greater the protection from ultraviolet rays, but the less wood grain shows through. Wax-based water repellents are often used after stain, but they, too, must be replaced frequently. Alternative deck materials such as polyethylene-clad wood may speed up product development of longer-lasting stains and treatments for wooden decks.


Why should you use protect the paint for wood decks?

From hardwood floors to countertops, from window blinds to decks, homeowners are increasingly seeking the natural beauty and warmth of wood. Of the 30 million residential decks in the United States, most are made of wood, especially pressure-treated wood. Most of the three million decks that will be built this year will also be made of wood.
For homeowners who want to stick with wood’s natural appeal, however, maintenance remains an obstacle. To keep treated wood decks from decaying and growing gray, deck-treatment manufacturers recommend d-i-yers clean their decks with special cleaners or power washers every year, and coat them at least every other.
Preserving consistent color on wood decks is difficult because the sun’s UV (ultraviolet) rays tend to fade treated lumber to a grayish hue.

The best way to protect a wood deck is to treat it with stains containing high amounts of pigments. The more pigments, the greater the UV protection. The downside? Stains mask wood’s appeal by reducing the visibility of the grain.
Aesthetically, clear treatments are most popular, but for function, they fall short. Transparent coatings offer little UV protection and force deck owners to clean and treat their decks more frequently.
Semi-transparent coatings, which contain some pigmentation, provide a look that’s closer to the original wood and more protection than clear coatings.
Some manufacturers, like Pittsburgh Paints, have developed semi-transparent coatings that provide up to two years of UV protection, the industry maximum.
“Very few people stain their decks,” says Tom Meth, manager of DMI Supply, a home improvement store in Ardmore, PA. Most use clear or semi-transparent coatings, he says. He’s waiting to hear from customers how the new, longer-lasting products perform.
Don Peshek, the technical services representative for Pittsburgh-based PPG Industries, Coatings and Resins, says UV stabilizers or inhibitors added to semi-transparent coatings can extend UV protection by only three to six months. He predicts no major developments in UV-blockers for more than two years.
Walter Gozdan, technical director for the Spring House, PA-based Paint Quality Institute, begs to differ. He says most deck coating manufacturers are working to develop better-quality treatments, but they all involve greater pigmentation.
Gozdan says transparent and semi-transparent coatings don’t show wear as much as opaque stains, but they offer less surface protection. Opaque stains wear unevenly and make re-coating more difficult. “It’s hard to get it looking even again,” Gozdan says.
Water repellents – mostly wax-based – make water bead on the surface, but, again, decks have to be regularly glazed with these products to prevent damage.

Gozdan recommends treating decks with UV protectors first, then with a water repellent.
For now, owners of wood decks have only manufacturers’ recommendations for regular maintenance. But as they see more decks built with maintenance-free alternatives such as vinyl, fiberglass, plastic composites and polyethylene-clad wood, they’re likely to demand deck treatments that last longer than current formulations, without diminishing the attributes that lead them to wood in the first place.

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