The TempZone™ twin conductor cable present in our TempZone™ products is comprised of a double-insulated, coaxial heating cable. The total thickness of the system can be between ⅛” and 5/32” thick and will not noticeably affect the height of your installed flooring. The heating system is encased in 3/8" of modified thinset or Self leveling underlayment. You simply use that 3/8" layer throughout the space, eliminating any need for fillers.