Single Ply roof systems are made up of factory fabricated sheets which come in rolls and are installed in the field as a single layer over the approved roof insulation. Single-Ply roof membranes are the most popular flat roofing product on the market today due to ease of installation and installation costs compared to the built-up roof systems. The three major single membranes are EPDM, PVC and TPO. They can be installed by these methods: Fully Adhered, mechanically attached, or loose laid with ballast stone. Prime is certified with the top single-ply roofing manufacturers and can provide roof warranties up to 30 years.