Concrete Floor Edge Insulation

Upgrading concrete slab floors.

Concrete floor edge insulation.

Ly 80 of the heat lost from a concrete floor slab is at the edge and that the thermal resistance does not significantly improve by fully extending the insulation under the slab or by increasing the thickness of the insulation under the slab see build 109 pages 28 29. The option to add exterior perimeter edge insulation to floor slabs is particularly pertinent for the rebuild of christchurch. Remember that the thermal envelope is the boundary between the inside conditioned space and the outside. 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.

This suggests that insulating slab edges is far more effective for preventing heat loss than insulating the underside. Such spaces typically have a sound level concrete slab floor but lack sufficient floor insulation to achieve the thermal performance targets for new habitable rooms. Where the heating is likely to be turned on and off such as in new build domestic properties and a faster thermal response is required the floating floor arrangement of insulation above the slab can be more appropriate. Insulation below the slab suits continuous low level heating gradually warming the thermal mass of the concrete and sustaining it at a consistent temperature.