Abstract: An underlayment mat for single ply roof membranes which provides the following: insulation, separate the roof membrane from incompatible materials in the substrate, protect the roof membrane from puncture or undue wear from irregular surfaces on the substrate, provide adequate support while being flexible enough to work with the single ply membrane to absorb shock and, or provide a continuous, flat upper surface on which a roof covering is applied. The underlayment member may be woven or unwoven, it may be spun bound or needled punched or constructed by whatever method best achieves the desired physical characteristics herein described at the most economical cost. Further, this mat may be made of the following materials including but not limited to and either individually or combined: Various synthetic fibers, acrylic, rayon, nylon, polyester, foam or foam scraps, and or mineral fibers such as glass, carbon, mineral wool, ceramic, and slag wood fibers.