wood and plastic composite is the leading building product used to build decks in America and in many parts of the world. Most composite deck brands are designed to give the appearance of real wood versus the composite material that it actually is. So although composite wood plastic boards may "look" natural, it's not. It is recycled material and must be treated as such.
The first thing you need to know is that while hardwood decking expands and contracts on its width due to environmental changes in temperature and moisture levels, composite outdoor decking will expand and contract on its length. This is an important distinction to make. You may be asking yourself why this is so important. Well, let's say that you construct your deck and place the ends of your deck boards right up against your home or other structure. As the temperature, precipitation, and humidity change, your composite deck boards are going to expand and contract on their lengths. Unfortunately, you have built your deck with the ends against a structure and they have nowhere to move. What happens next is a lot of unwanted cupping and warping issues.
Another problem you may face is deciding how to install your composite wood plastic boards. Many builders say that screwing directly through the top of the board is just fine. I couldn't disagree more. Face screwing may mean that your finished deck will look decent from a distance, but the closer you get, the more screw heads you will see. There are certainly a number of naysayers out there that point to a selection of screws that have colored heads that help make them blend into your deck boards. Sure there are, but what they aren't telling you is that face screwing completely avoids the most common problems associated with face screwing, which is mushrooming, mold, and decay.
Let's explore this further. Let's say you rush through your WPC decking installation. Screws are everywhere in the top of your deck! Now, fast forward a few months, a year, maybe even two. There's been a lot of rain, maybe some snow, ice, and a lot of time for water to sit and rest around the heads of each screw. Gravity being what it is...at least SOME water will seep into the crevices that arise. Where did these crevices come from? Think about it. Those screws are driven through the deck board into the joist so that your composite wood plastic boards won't move. But, if you remember from above, all types of decking will move. So, with this in mind, the decking moves on its length and the screw...well, does it stay in place? No, it will move around too. These movements can be incidental or they can be noticeable right away depending on how well the decking was manufactured and/or the climate you are in. Regardless, the result of water seeping into the screw hole will lead to mold and eventually decay. Two things that will make any deck look horrible and require you to have to replace it years sooner than it should have.