Vinyl decking is a low maintenance waterproof decking option constructed of PVC (polyvinyl chloride). The 2 most common types of vinyl decking are: PVC Sheet Membranes (like Duradek vinyl membranes) and Cellular PVC (sometimes mistaken for composite decking). PVC Membranes are an attractive, textured sheet vinyl applied to a solid surface (like untreated plywood) and provide a water-tight seal to keep the space below dry - perfect for elevated decks or flat roof decks over living space. Cellular PVC decking consists of boards (like traditional slotted wood decks) allowing water to pass through the deck boards to the area below.