In a roofing recovery application, the last thing you need is to struggle with underlayments that are heavy, break apart, or turn to mush when wet. With GreenGuard PB6 products, you get underlayments that are easy to use and dependable for re-roofing with single-ply membranes. PB6 boards are 3/8” thick extruded polystyrene (XPS), making them lightweight and durable. They provide excellent moisture resistance, with a water absorption rate of less than 1%. Plus they are easy to handle and cut with a utility knife. All of this combines to give you an easier installation and lower total cost. Boards are available for mechanically attached applications with EPDM, TPO and PVC single-ply membranes.