Rigid Insulation Under Slab Detail

For under slab applications the rigid foam insulation typically should be installed over a gravel base with a poly vapor diffusion retarder between the gravel and insulation.

Rigid insulation under slab detail.

4 10 2012 3 climate zones e301 1 6 5 8 4 slab r value table 402 1 1 insulation and fenestration requirements by component e402 1 1 climatezone slab r valued 4 10 2 ft 5 10 2 ft 6 10 4 ft 9. It is installed on the interior exterior or is integral to any opaque surface of the building envelope. Set your store to see local availability add to cart. Insulation located below grade as required in climate zones 4 through 8 should extend the length specified in the table by any combination of vertical insulation insulation extending under the slab or insulation extending out perpendicular to the building insulation extending perpendicular away from the building should be protected by.

Roche has paused at an important detail. Figure 4 11 illustrates a slab on grade foundation with a masonry foundation wall. Rigid insulation is placed vertically on the exterior face of the foundation wall. In climate zones 6 7 and 8 by any combination of vertical insulation insulation extending under the slab or insulation extending out from the building.

The layer of rigid foam insulation that separates the concrete foundation wall on the outside from the slab on the inside. Code requirements for slab insulation are very poorly written. Depending on the use of the building the slab can then be finished ready for use or receive a screed suitable for a floor finish. If the insulation is going below the slab the damp proof membrane dpm is laid next followed by the insulation a polythene separating layer and the concrete slab.

Insulation requirements for slab on grade floors can be found in section r402 2 9 of the 2012 iecc and 2015 iecc as well as section n1102 2 9 of the 2012 irc and 2015 irc. Moisture control is provided by a vapor retarder under the slab. This compliance option is explained this way. This insulation aligns with rigid foam sheathing that covers the framed walls above grade.

Roche writes in a recent q a post that just about every foundation design for a slab that he s seen either puts all of the rigid insulation on the outside of the foundation or. Insulation located below grade shall be extended the distance provided in table n1102 1 1 namely 2 ft. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the building materials department. R 7 7 rigid foam insulation model 310891 18 35 18 35.

Additional insulation is applied along the edges of the slab because that is a primary surface for heat loss.