In general, composite decking is manufactured from wood fiber and plastic to form a plank that requires less maintenance and typically has a longer lifespan than natural wood decking.
Composite decking is made from one of several polymers—polyethylene (low-density or high-density), polyvinyl chloride and polypropylene—plus wood flour and additives that stabilize the plastic and protect it from damaging UV rays. Most wood fiber is ground to a fine consistency—like flour—allowing for a more uniform look throughout the board.
One major reason composite decking is low maintenance; It does not take in or give off moisture, so it does not shrink or swell like wood. As a result, composite decking does not crack, warp or separate due to varying weather cycles. Composite decking resists insects, does not need water repellant or stain and can hold up to extreme weather conditions for decades. In addition, builders like to use composite decking because it cuts and installs like real wood.