Kinds of Deck Material

Building a deck or adding on to one you already have is a way of expanding the living space of a home.  A deck or patio is much more inexpensive than a complete addition to a home.  It might not, technically, be living space, but a nice deck will add space you can utilize during the warm months of the year.  
You can build a deck out of various materials.  Wood is still the most common material used but there are different types of wood you can use.  Composite and PVC are other common choices.  Let's look at the options.
Wood decking materials are easy to find and build.  They can be Pine, Cedar, Mahogany, or other species.  The important thing to look for here is green treated lumber.  Lumber that is green treated will not decay as quickly as untreated lumber.  Since a deck is outdoors in the weather elements year-round, it is important to protect your wood decking materials as much as possible.  Green treated lumber is the first step.  The species of wood you choose isn't a make-or-break decision.  They all look good and they all need regular maintenance to get them to last longer.  All wood decks should be cleaned and resealed every two years at a minimum.  Every year is better but every two years is almost as good.
Composite decking materials have been around a while now and their popularity has plateaued.  Composite materials are made from various post-consumer products like plastics and woods.  They will last longer than wood with less maintenance but they have some cons of their own.  Composite decking materials are known to allow mold growth.  This will depend on your climate and can easily be washed off but it is something to keep in mind.  Composite decks will, also, expand and contract much more, with the temperature changes, than wood.  This is rarely a problem for homeowners, however.  The color can fade quickly with composite boards and some styles are quite slick when they get wet.
PVC decking materials are relatively new to the market but have already left their mark.  PVC is virtually, maintenance free and can be cleaned with a garden hose.  PVC decking materials now come in several different colors, including earth tones so you don't have to settle for white vinyl.  PVC will be more expensive than other materials to build with but it will last much longer and require much less maintenance.  To reduce the cost a little, you can look for PVC covered composite.  Some of these simply, have PVC covering one side to protect it from the weather.