Polyurethane is replacing polyester for a number of reasons. First, the cycle time is faster, thereby increasing productivity. Polyurethane and polyurea systems can be designed to cure in seconds and to be handled in minutes, depending upon the particular application. Second, polyurethane is less sensitive to moisture than polyester, contains more solids and is lower in VOC’s, making handling easier and less expensive. Cured polyurethane is also less prone to shrinkage than polyester. Finally, polyurethane lamination can be applied to the substrate in a continuous application to the desired thickness, making production time quicker than rolling out fiberglass with polyester lamination.