Thermoplastics TPO Single Ply Thermoplastic single ply membranes are revolutionizing the commercial and industrial roofing industry. They represent the fastest growing segment of the U.S. roofing market over the past five years. The TPO (thermoplastic polyolefin) product advances the category yet another step by combing the hot-air welding benefit of PVC with the greater flexibility and weatherability benefits of EPDM, the more traditional single ply material. TPO is aesthetically pleasing, lightweight, highly reflective, and is tear resistant. It also offers excellent fire resistance.