Rigid Insulation Under Slab Detail

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.

Rigid insulation under slab detail.

In climates zones 4 and 5 and 4 ft. Moisture control is provided by a vapor retarder under the slab. 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. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the building materials department.

Additional insulation is applied along the edges of the slab because that is a primary surface for heat loss. Rigid insulation is placed vertically on the exterior face of the foundation wall. 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. 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.

Continuous insulation is defined in 90 1 as insulation that is continuous across all structural members without thermal bridges other than fasteners and service openings. 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. Roche has paused at an important detail. In fact they are almost unintelligible.

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. R 7 7 rigid foam insulation model 310891 18 35 18 35. This compliance option is explained this way. Figure 4 11 illustrates a slab on grade foundation with a masonry foundation wall.

Insulation located below grade shall be extended the distance provided in table n1102 1 1 namely 2 ft. Code requirements for slab insulation are very poorly written. This insulation aligns with rigid foam sheathing that covers the framed walls above grade. The layer of rigid foam insulation that separates the concrete foundation wall on the outside from the slab on the inside.

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.