Thermal mass is is the ability of a material to absorb and store heat energy, the denser the material, the greater the thermal mass. Concrete; being incredibly dense, is an excellent thermal mass and when controlled, can significantly reduce the energy required to heat and cool a building. Insulating the slab and foundations of a building reduces the external temperature fluctuations resulting in reduced energy costs.
Underslab foam insulation is available in two different types:
XPS – Extruded Polystyrene Foam is a high density foam with excellent thermal resistance and is impervious to water.
EPS – Expanded Polystyrene Foam is a lower cost, medium or high density foam with a lower thermal resistance to thickness ratio.