Co-Extrusion Solid Deck Flooring  is also called "capped" or "cover" decking using the latest technology co-extrusion. Before Co-extrusion decking, the composite decking was uncapped, but Co-extrusion WPC has a "cover" that provides added protection against the elements and everyday living while the extruded surface is made of multi engineer plastic with an outer shell of plastic that completely encapsulates the board in an impermeable layer of protection from scratches, stain and fading. Co extrusion composite decking is the smart way to get a great-looking, long-lasting board. The shield and core are extruded simultaneously, so there are no adhesives or chemicals that are harmful to the environment.