Decking made from a mix of plastic and wood--such as Trex, ChoiceDek, and TimberTech--is an excellent alternative to wood because it won't warp, rot, or splinter. Plus, these products withstand termites and other bugs, offer a uniform color, and won't fade, so you don't need to fuss with stains or sealers. Because wood composites are water resistant, they're perfect for docks and other surfaces near the water.
The composites do have a couple of drawbacks. They are somewhat more expensive than pressure-treated wood and aren't as structurally sound. Use them only for the decking surface or as handrails; never use wood composites to frame a deck or as structural supports. This material falls in the price range of $4 to $5 per square foot.
Cedar and Redwood
These woods are known for their natural resistance to disease and rot. They're both durable and easy to cut, but because they are soft, cedar and redwood can split. Predrilling holes is a good idea. They can also be scratched or gouged by sliding furniture across the surfaces. Both woods are quick to weather and gray, so applying a sealer with UV protection is a must. Some sizes may also be difficult to find. Cedar and redwood fall in the price range of $4 to $6 per square foot.
Mahogany and ipe are high-end options. Mahogany has a tight grain and is naturally a beautiful red color. Only purchase mahogany that's been harvested from a managed forest because certain species are endangered. A great material for the floor of a covered porch, it should be sealed to keep it from cracking and splintering. Mahogany is the most reasonably priced of the exotic woods at around $4 per square foot.
Ipe is incredibly dense, which means it only needs to be sealed once. It's virtually knot- and splinter-free, weathers beautifully, and is impervious to bugs and rot. It's an expensive option at $5 to $6 per square foot and must be predrilled, which drives up labor costs.