Should I use Self-leveler or Thinset ?
Loose Wire – NADWS
You can thinset and tile directly over your mats or cables. We recommend if using thinset and tile directly over a mat system that you place the heater wires facing down and the mat side facing up. This will not affect the efficiency of the cables but adds another element of protection for when troweling. We also recommend using a plastic trowel.
Leveler can be used to avoid possible nicking the wires while tiling and serve as added protection against damage. If you are not going to be tiling immediately after installation, thinset might be a great option for you. It will ensure that foot traffic or accidents do not cause your cable to become damaged. Additionally, if you are installing mosaic tile, self-lever is required prior to installing tile.