What Kind of Wood Is Used to Build Decks?

Softwoods

• The vast majority of decking materials are softwoods. The most commonly used are redwood, cedar and cypress, mostly because they contain oils that resist rot, but also because they are abundant -- redwood especially so in western regions of North America and cypress in the South. Fir and pine, while not as appropriate for decking materials, usually form the foundations of decks. There are several methods for pressure-treating them with chemicals that render them resistant to rot and fungus. Although some of the chemicals in pressure-treated wood are toxic, the wood is usually safely out of the main usage area of the deck.

Hardwoods

• Because they are harder to work with and cost more, deck builders tend to shy away from hardwoods. An exception is a Brazilian hardwood known as ipe. A type of teak, it is farmed on plantations and milled into 6-inch boards with thicknesses of three-quarter and 1 1/4 inches. Ipe is very hard and installing it requires special techniques, but it lasts significantly longer than softwoods and has an attractive reddish-brown hue. Ipe costs significantly more than other decking materials, but the cost can be offset by the extra years of service it provides and the fact that it is a sustainable product.

Composite Decking

• Composite decking boards are not exactly wood, but they do contain wood fibers, as well as recycled plastic, much of it from old plastic bags. Composite boards do not have enough structural integrity for use in deck foundations, but they can be used for railings, fascia and stair treads. They are low maintenance, when compared to real wood boards, and aren't subject to the defects that develop on wood after exposure to rain and sun. They can still deteriorate over time, however, if you don't install and take care of them properly.

Plywood

• It is possible to cover the surface of a deck with plywood, but the plywood must be well coated because it does not drain well. Instead of falling between cracks, as it would from the surface of a deck with spaced decking boards, rain tends to collect on plywood. If the plywood is uncoated, or covered only with paint, the rain will soak in and rot it. An effective coating may be provided by sheet vinyl or a spreadable rubberized plastic. The best deck on which to use plywood is one that has a roof.