There will be a damp proof membrane under the insulation and possibly a second membrane on top depending on the type of screed.
Thermal floor insulation.
A good quality insulating underlay will act as a high quality thermal barrier.
In this scenario a rigid foam insulation is usual and as you d want the same u value in the roof we need the same thickness of insulation 180mm.
Achieving greater r values in exterior walls in exterior walls add insulating sheathing to achieve a greater r value in your wall system.
Without lifting solid floors it s difficult to introduce any permanent thermal insulation but coir or other breathable floor coverings can help.
You can achieve better thermal performance in your attic by adding an additional layer of insulation.
Especially when used over a concrete floor or draughty floorboards.
Insulation is laid on the concrete and covered with a screed.
But it isn t the only factor when choosing the right product for your home or building.
Avoid covering the floor with impermeable insulation materials or rubber backed carpets as they ll trap moisture.