Earthwerks WPC (Water Proof Core) is a composite material made of PVC. WPC is extruded as a core material and is water proof, rigid, and extremely dimensionally stable. WPC products have a distinct advantage over other vinyl products since the rigid core hides subfloor imperfections, in addition the rigid core allows for longer and wider installations. WPC has been designed to address concerns over sounds absorption, high humidity and wet environments, and dimensional stability such as gapping and expansion. Earthwerks WPC core is composed entirely of 100% virgin PVC with no plasticizers, and no fibre glass thanks to our special ‘recipe’ and annealing process.