We frequently receive questions about what the best material to use for new decking. There are several products out on the market, each with their own benefits and drawbacks:
Redwood, Cedar: These two softwoods are traditionally used for wood decking. They have a nice appearance, but require staining and upkeep to look their best. Because they are softwoods they also weather and eventually rot faster than some alternatives.
Composite Decking: Composite or Plastic Decking is a synthetic product made of a composite of wood particles and plastic. Is requires much less maintenance than traditional softwoods, and is rated for a longer life span. The drawback of the composite decking is its appearance. While new technologies and products are available that are more realistic looking, they still do not fully approach the beauty of natural wood.
Hardwood Decking: Brazilian Walnut (also known as Ipe or Pau Lope) is a tropical hardwood that is several times stronger, denser and heavier than softwoods. It is highly fire resistant and has great structural properties. Unfortunately it is also the most expensive of the three options. The wood has a beautiful appearance stained (like that of a fine interior hardwood floor) but requires continual repeated staining in exposed areas (once per year). If the wood is not stained it can be treated with a wood seasoner (Seasonite) and allowed to turn silvery gray (think weathered teak).
A Decking Article from Bob Villa