EPDM (ethylene propylene diene terpolymer), by nature, is a black thermoset membrane which can’t be remolded or welded. As a result, seams must be taped or glued as opposed to being welded together like TPO or PVC seams. For years EPDM has been losing market share to competing white single-ply thermoplastic membranes. That does not mean that EPDM does not have a place in the current roofing market. There are many scenarios that EPDM may make sense. As an example, in a re-roof scenario on a building that has existing ballasted EPDM membrane, structural calculations may require the ballast to remain on the building. In that case, replacing the existing EPDM with new EPDM membrane may provide the most durable roof system scenario. Also, reflection from a white single-ply roof may create a problem on a multi-story building with lower roof areas. If a white membrane is used, light may reflect onto the side of the building and into the windows above creating unsightly aesthetics and an uncomfortable atmosphere for employees or owners.