As a decking material, acomposite excels. Made from virgin or recycled plastic and wood waste, composite is durable, weather-resistant, and virtually maintenance-free. But while those attributes may satisfy your clients' practical side, the product's ersatz appearance may leave some of them feeling a little unsatisfied. For those consumers, only a wood deck will do.
Architects value the seductive powers of wood more than anyone; that's one of the reasons you spec it. Its random grain patterns are inherently beautiful, and wood can last a long time if properly cared for. “We prefer [Forest Stewardship Council]-certified natural wood for aesthetic and sensory reasons,” says William T. Ruhl, AIA, of Ruhl Walker Architects in Boston. “Natural wood looks better and feels better on bare feet.”
natural selections Pine and Douglas fir are the most common and inexpensive species used for decks. Doug fir is strong, attractive, and tough. It holds up fairly well to extreme wear and remains level without cracking. Typically pressure-treated to resist weather, rot, and insects, Southern pine's unique cellular structure permits deep penetration of preservatives, providing long-lasting protection, says the Kenner, La.–based Southern Pine Council, a promotional body that represents Southern lumber producers.
Despite their resiliency, however, these two species lose their luster after prolonged exposure to the elements, and they need replacing after 10 to 12 years, depending on the climate. Some architects avoid them for other reasons. “Pressure-treated pine is cheap up front, but the splinters are awful,” says Ruhl.
Fortunately there are plenty of other deck-worthy trees in the forest, among them teak, Western red cedar, redwood, and mahogany. The lumber from these trees has exquisite grain patterns and its natural weather- and insect-fighting properties will keep your outdoor decks attractive for a long time.
Although prized as one of the world's premier woods for fine cabinetry, mahogany is strong and dense enough for outdoor use and has natural rot-resistant properties. Teak and Western red cedar are rich in natural oils that make them extremely resistant to moisture as well as the drying effects of weather. And the oils in Western red cedar also act as a preservative to help the wood resist insect attack.
Moisture in the Pacific Northwest is one reason Seattle-based architect Nils Finne is a fan of Western red cedar. “We have also used redwood in California,” he says. “It is beautiful, but the wood is somewhat soft so it needs fairly regular maintenance.”
The same applies to Atlantic white cedar, says architect Timothy Techler, principal of Techler Design Group in Watertown, Mass. “The wood is very soft and it goes a silvery gray color,” he says. “You have to be careful with it, but it is lovely stuff.”
The budget and the exterior finish of the house usually dictate what San Francisco–based Melander Architects uses. “If the project is on the moderate end we use Doug fir,” says Aaron Goldman, an architect with the firm. “On the high end, we have used redwood.”
Possibly the hottest tropical species at the moment is Ipé (a.k.a. Ironwood). “Ipé is amazing stuff,” says Techler. “It is heavier than water, so it does not float, and it handles the wet-dry cycle better than other woods.” As its Ironwood moniker suggests, Ipé (pronounced e-pay) is extremely hard and dense, weighing 70 pounds per cubic foot. It does not accept preservatives well, but it doesn't need to. The lumber has the highest natural rating for rot and insect resistance with no treatment, the USDA Forest Service says. Austin, Texas–based architect Tom Hurt knows this first hand. The harsh Southwest sun can wreak havoc on a wood deck. No matter what you use, he says, the sun takes its toll. “Ipé is different,” the principal of Tom Hurt Design Office says. “It is a lot more stable and looks better longer. If you don't treat it, it will gray out, but it will still look good.”