Capstock is a new kind of composite decking material that combines composites (plastic and wood fiber core) with a “durable” exterior layer of vinyl (PVC). Think of it as a composite and PVC deck hybrid. Like with most new products in the decking market, the companies that sell this kind of synthetic decking are doing their best by spending millions of dollars to convince you that, FINALLY, this is a composite wood product you can trust. These brands are also trying their best to convince you and deck builders across the country that it is “as good as, or better” than natural hardwood decking in terms of durability and looks.