Mat System The mat electric floor heating system consists of a mat with the cable heating elements pre-spaced 3" within the mat. Simply unroll the floor heating mat with the cold lead running up the wall to the electrical box. These heating systems are ideal for rectangular or square areas with right angles. You can manipulate the mat to fit the desired heating area by using the turning techniques as shown on page 6 in the installation manual. The white fiberglass mesh may be cut to flip and turn the mat. The RED HEATING ELEMENT CAN NOT BE CUT, so be sure to accurately measure the space you are heating. For assistance please see Tips for Choosing the Right Size System. This system must be completely embedded in a self-leveling mortar 1/4" to 1/2" thick. Use only polymer modified cement based mortars. The heating system should be installed on concrete or concrete backer board.