Thermal Break For Concrete Floors

Concrete placement shows concrete being placed on the top of the sheet polyethylene and a layer of xps insulation.

Thermal break for concrete floors.

Photograph 4 is a thing of beauty. In older details a timber strip was used but branz bulletin 576 edge insulation of concrete floor slabs shows a new detail that incorporates a 10 mm thick strip of xps with an r value of r0 25. Remember that the thermal envelope is the boundary between the inside conditioned space and the outside. The bars tie into the rebar.

A thermal break to the perimeter of the floor slab between the slab edge and the foundation greatly increases r value. A schöck isokorb structural thermal break is a fabricated assembly that is cast into the concrete floor slab at the location of the building insulation layer. Stones gravel keep the plastic from blowing away. Rigid foam is a nice option because it provides an excellent thermal break between concrete and flooring.

Any gab in this thermal envelope is an avenue for heat loss known as a thermal bridge. The sides of the concrete slab also referred to as the perimeter wall is often forgotten or not considered at all with respect to the thermal envelope. Notice that there is no welded wire mesh.