TremPly KEE and KEE FB (fleeceback) are additions to the company’s line of single-ply roofing systems. Both contain Ketone Ethylene Ester (KEE), which provides superior flexibility to accommodate building movement, as well as resistance to harmful UV rays and chemicals. Heavy-duty reinforcement reportedly makes the systems extremely resistant to tears and punctures, and combines with maximum seam strength for durability and long-term performance. They are resistant to fungus, algae, and fire. The systems are available in mechanically attached or fully adhered configurations, with seams fused with conventional hot-air welding, in 45-mil and 60-mil thicknesses.