Rigid Insulation Under Slab Detail

Figure 4 11 illustrates a slab on grade foundation with a masonry foundation wall.

Rigid insulation under slab detail. Rigid insulation is placed vertically on the exterior face of the foundation wall. In fact they are almost unintelligible. Roche has paused at an important detail. 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.

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. R 7 7 rigid foam insulation model 310891 18 35 18 35. Insulation located below grade shall be extended the distance provided in table n1102 1 1 namely 2 ft. It is installed on the interior exterior or is integral to any opaque surface of the building envelope.

Moisture control is provided by a vapor retarder under the slab. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the building materials department. Code requirements for slab insulation are very poorly written. Additional insulation is applied along the edges of the slab because that is a primary surface for heat loss.

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. 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. Set your store to see local availability add to cart. 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 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. 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. In climates zones 4 and 5 and 4 ft.

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.