Thermoplastic roofing membranes, one of the fastest growing forms of low-slope roofing products, come in different material families, including thermoplastic olefin (TPO), polyvinyl chloride (PVC), and PVC alloy. Some attributes shared by TPO and PVC membranes include long-term weathering resistance, cold temperature flexibility, resistance to tear, puncture, and chemicals, and heat-seaming capability.