Floor Slab Insulation Thickness

Ground bearing floors can include insulation either below or above the concrete slab the choice the designer makes will have an impact on the temperatures inside the building as follows.

Floor slab insulation thickness.

Insulation sheets should be laid tightly together with the joints staggered to avoid movement. Protect the exposed top of the perimeter insulation from any damage until covered by skirting or wall finish. There will be a damp proof membrane under the insulation and possibly a second membrane on top depending on the type of screed. Insulation is placed below the concrete floor slab.

Insulation requirements for slab on grade floors can be found in section r402 2 9 of the 2012 iecc and section n1102 2 9 of the 2012 irc. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the. The insulation is then laid followed by a polythene separating layer and either a concrete screed or tongue and groove chipboard ready to receive the specified floor finish. In this scenario a rigid foam insulation is usual and as you d want the same u value in the roof we need the same thickness of insulation 180mm.

2x4 wall 2 2x6 wall 2 attic 2 basement 3 crawlspace 2 exterior sheathing 3 exterior wall foundation 4 floor 1 garage 3 under slab. There are fewer restrictions on the thickness of the insulation in comparison with above slab insulation and there is less of an issue with point loading as the load is spread over the slab rather than the insulation. 2015 iecc irc section r402 2 10 n1102 2 10 slab on grade floors. Insulation below the floor slab.

Both codes state slab edge insulation is not required in jurisdictions designated by the building official as having a very heavy termite infestation. Where insulation is positioned above the slab the slab and dpm can be installed either way round. Insulation is laid on the concrete and covered with a screed. A 50mm thick layer of proprietary floor slab insulation is usually enough to reach and maintain the target u value but this should be checked with an architect first.

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. Product thickness in 2 in 2 1 5 in 1 2 375 in 1 3 in 1 insulation location. The edge insulation should be at least 25mm thick and height should extend from the top of the concrete slab to the top of the finished floor screed.