Definition FOX EPOTHANE® ISO-CRACK EP-2K is a flexible epoxy-polyurethane membrane based on 100% solid material designed to prevent cracks that will be reflected on the surface in Fox Bau Terrazzo coating systems. The unique bonding and elongation properties of the resin provide exceptional crack bridging and it is recommended for use on internal concrete surfaces prior to laying the floor. It provides 140-160% elongation, which allows horizontal surface movement.