Floor Slab Insulation Thickness

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.

Floor slab insulation thickness.

There will be a damp proof membrane under the insulation and possibly a second membrane on top depending on the type of screed. 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. Lightweight rigid polyisocyanurate pir foam insulation boards such. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the.

Insulation sheets should be laid tightly together with the joints staggered to avoid movement. Both codes state slab edge insulation is not required in jurisdictions designated by the building official as having a very heavy termite infestation. If the insulation is installed below the slab the thermal capacity of the building is increased helping to maintain steady internal temperatures. 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.

Insulation below the 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. 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. 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.

Insulation is laid on the concrete and covered with a screed. 2015 iecc irc section r402 2 10 n1102 2 10 slab on grade floors. Slab on grade floors with a floor surface less than 12 inches below grade should be insulated in accordance with information provided in the insulation and fenestration requirements by component table which is reproduced following this paragraph. 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.

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. Where insulation is positioned above the slab the slab and dpm can be installed either way round. Insulation is placed below the concrete floor slab.