Composite decking is made from a combination of plastic and wood (from sawdust and other lumber byproducts), which is processed to look like wood. Although composite decking isn't as strong as wood, it's heavier, doesn't warp or give splinters, and it doesn't need to be stained, sealed or painted; so it's a good choice if you don't want to have to deal with the maintenance a wood deck requires. Stains and spills do need to be attended to promptly, though, and it should be scrubbed and hosed down twice a year [source: Decks].
You can get solid or hollow composite decking. Solid is more popular because it's heavier and looks more like wood [source: Montenegro], but it expands and contracts more when temperatures fluctuate. Hollow composite decking is susceptible to damage before installation. Most composite decking is made of 40 to 70 percent wood [source: Carter], so it needs to be treated with preservatives and antifungal chemicals to prevent it from rotting when it gets exposed to the elements.
Composite decking may be polypropylene-based, polyethylene-based or made of entirely nonwood plastics. Polypropylene-based products are stronger and less likely to expand and contract. PVC (polyvinyl chloride)-based products are made of plastics with no wood content, and they neither stain nor absorb water. These are lighter than other composites, more expensive than wood, and they usually have no recycled content. Some composite decking is more fade-resistant than others, which is also something you'll want to take into account. You'll have to consider where the deck will be located, how it will be used and what texture and color you want it to be when deciding what kind of deck you want to build [source: Decks].
Installations costs for composite decking are comparable to those of wood decking. They use the same foundation but composite decking requires more gapping between boards to accommodate expansion and compression.