Non-structural 6mm thick expanded polystyrene insulation board specifically for use in conjunction with electric underfloor heating on solid concrete floors.
Thermolite can be stuck down using the same 1-part flexible rapid set adhesive required for your underfloor heating mat or cable
Don’t kid yourself that you don’t think you need insulation! – if you don’t use an insulation board your electric underfloor heating won’t work properly and you will waste money warming up the concrete, and not the tiles that you have fixed to it, nor the room that you want to be a pleasant warm place to be.

Measurements: 1200mm × 600mm × 6mm