The biggest types of PVC (poly vinyl chloride) roofing products are TPO or TPC which are 'Double Coated' sheets. These sheets have a PVC layer
on both sides of the sheet.
Commercial roofing sheet products are made from multiple layers of PVC with additives to enhance its characteristics and reduce its costs. Most sheets are made in rolls about 50 feet long by 15-20 feet wide, but there are also smaller 4x8 sheets available (for example for installing over existing metal roofs).