This is a pretty good article from Inman News that I thought that I would post for you to see...  

Composite decking not infallible

Despite benefits over natural wood, warping and rotting still possible

Check over the results of virtually any home improvement survey, and you will see that adding a deck consistently ranks at or near the top of the list in terms of both desirability and payback on investment. If a deck is high on your wish list, one of the primary decisions you are no doubt struggling with is what type of decking material to use -- natural wood, or one of the new plastic composite materials that have been getting so much attention lately.

The relative advantages and disadvantages of natural wood are pretty well known. On the plus side, there is the pure, natural beauty of wood, something the composites have been striving with mixed results to emulate. In the eyes of many homeowners and builders alike, nothing can ever replace the subtle grain variations and smooth glow of a piece of redwood or cedar, or one of the hardwoods such as teak or Ipe.

Then there are the obvious drawbacks to wood, which include splintering, cracking, insect and water damage, and the need for regular maintenance every one to two years. It's a tough balancing act between looks and upkeep.

So, enter the composite decks, one of the faster-growing segments of the building material industry. They have been heavily marketed, with the consistent underlying theme being that composites offer much of the beauty of wood without the hassles. True or not?

Actually, most of the main selling points of composite decking seem to be true, if occasionally a little overoptimistic. Composite decking is typically a very stable material, without the cracking and splintering associated with natural wood. You're not going to pick up a splinter walking across one of these decks, and they are also a pretty undesirable meal for an insect.

Low-dimensional shrinkage -- the tendency for a 6-inch-wide board to stay 6 six inches wide after exposure to the elements -- is also an advantage to composite decking. However, to say unequivocally that these materials will not warp would be a bit of an overstatement. There is still that possibility, and it's imperative that the manufacturer's rated spans not be exceeded, and that there is sufficient support and an adequate number of fasteners used.

While the exact composition of composite decking materials varies, they are in large part made from recycled materials, another definite advantage. Some of the decking materials can also be recycled themselves should the time come to remove the deck, but that's something you should clarify when you're shopping and comparing brands.

While virtually all of the composite decking materials contain some form and percentage of plastic or vinyl, many also contain a certain amount of wood fiber. Even though the wood fiber is blended with the liquid plastic during the manufacturing process, it is not completely impervious to rotting. The percentage of wood fiber in the makeup of the material is another consideration when shopping, and it's generally considered best to look for a product with less than 50 percent wood fiber in it.

While composite decking may not have succeeded completely in its quest to duplicate the beauty of natural wood, it's still a very attractive material in its own right. Composite decking now comes in a wide variety of colors and texture patterns, and the ability for a deck designer to select a color that blends with the deck's environment, or even to combine colors for dramatic effect, is one of the material's chief advantages. Curves are also typically easier to achieve with composite materials than with natural wood, although tight curves and intricate designs can still present some challenges to the deck builder.

That brings us to maintenance, one of the primary selling features of composite decking. Compared to natural wood, composites really do win this battle hands down, with none of the regular applications of stains and sealers associated with wood. They are not completely maintenance-free, however, and it's important that you follow the manufacturer's instructions for regular cleaning in order to maintain the best appearance. Certain substances can stain composites, such as grease from the barbecue, so it's also important that spills be cleaned up quickly and thoroughly.

Finally, there is the question of durability over time. Composites have simply not been around long enough to be able to say with complete certainty that they will or won't perform well after 10 or 15 years in the backyard. And don't be suckered in by an attractive warranty. As with virtually all building materials, the typical warranty has so much legalese in the fine print and so many exclusions for everything from improper storage at the dealer's yard to installation methods that don't strictly adhere to the manufacturer's sometimes unreasonable standards as to be pretty much useless.

If you're thinking about a composite, your best bet is to simply shop around, ask questions and do your homework. Then ask the dealer or decking contractor for the names of several people who've had similar materials in place for three years or longer, and go check a couple of them out to see for yourself how they're holding up, and what the owner's experiences with them have been.