Although it is not essential to have insulation directly under the heating mat or cable, we do strongly recommend it.
Insulation will reduce your running costs and shorten the warm up time of your underfloor heating.
The Ekoboard insulation boards are suitable providing that the floor base is level, load-bearing and there is no movement in the floor.
If there is a chance of movement, or the floor is uneven we would recommend Thermopanel Insulation Boards are used as an alternative to Ekoboard.
With insulation board thicknesses available from 6mm to 50mm, the insulation boards you choose for use in your project will depend on the depth you have available. The greater the depth of insulation, the more efficient it becomes - though of course any insulation whatever the thickness is better than no insulation.
Both Ekoboard and Thermopanel are both made from XPS insulation, and both have the same high insulating and compression properties. The only difference is that Thermopanel has a cement/mesh layer either side of an inner insulation board, making it more rigid than an Ekoboard. This means it is perfect to be installed on top of uneven non-solid floors such as old floorboards.
If you have a solid floor such as concrete, plywood, chipboard or similar, Ekoboards are perfect as you will get the rigidity needed from the existing floor base.
Ekoboard comes in 6mm, 10mm, 20mm, 30mm, 40mm & 50mm thicknesses and are made from XPS to give it rigidity and insulating properties.
Thermopanel comes in 6mm, 8mm, 10mm, 12mm, 15mm, 20mm, 30mm, 40mm & 50mm thicknesses. All have a very high compression strength, and a good indication of this strength is that you will be able to push your nail into the board, but you will not ever be able to dent any of the boards pushing your whole hand into it as a spread weight.
For our VCD17 In-Screed Heating System, we would always recommend that the heating cable is installed directly onto a foil backed Celotex or Kingspan insulation board, the thickness of this board depends on building regulations and the depth you have available.