Insulated Concrete Floor Slab Detail

This stops any thermal bridging across the walls leading to cold spots.

Insulated concrete floor slab detail.

The layer of rigid foam insulation that separates the concrete foundation wall on the outside from the slab on the inside. The target u value for a concrete ground floor slab is 0 22 and these days the insulation must be provided around the edge of the floor slab as well. Insulation below the slab suits continuous low level heating gradually warming the thermal mass of the concrete and sustaining it at a consistent temperature. Ground bearing floors shall be of adequate strength and durability and use concrete mixed and reinforced as necessary to support floor loads safely and resist chemical and frost action.

In this section several typical slab on grade sections are illustrated and described. Figures 4 12 through 4 14 show variations where the slab is the primary location for insulation. These f factors are acceptable for all slab on grade floors but you need to make sure. Martin holladay explains insulating a slab on grade in the energy smart details department.

The slab on grade design calls for double stud walls insulated with dense packed cellulose what roche believes is the most economical and practical approach for getting the walls to r 40 or beyond. Perimeter slab insulation heat loss through an insulated slab windows 33 roof ceiling 8 slab 15 6 doors 5 walls 39 insulation and fenestration criteria table 402 1 1 insulation and fenestration requirements by componenta climate zone fenestration u factorb skylightb u factor glazed fenestrationb e shgc ceiling r value wood frame wall r value. Consult appendix a table a6 3 1 in the 2016 edition for a tabulation of assembly f factors for slab on grade floors based on the arrangement and rated r value of the applied insulation. 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.

If headroom is tight then the only option may be to break up the existing slab dig further down and build up an entirely new floor. 4 2 slab on grade construction details. Figures 4 9 through 4 11 and 4 15 show configurations with insulation on the exterior surface of the foundation. The climate the type of foundation whether the slab includes hydronic tubing for radiant heat and the severity of the local termite problem.

Insulating a slab on grade depends on at least four factors. 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.