Insulation Under Garage Floor Slab

Concrete is cold and hard but an insulated concrete slab can make a heated garage significantly warmer and more energy efficient.

Insulation under garage floor slab.

Otherwise both codes require that slab on grade floors with a floor surface less than 12 in. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the building materials department. But when adding insulation to an existing slab the vapor barrier is laid over the top of the slab before the foam insulating panels are installed. Floor 1 garage 3 under slab 5 more ways to filter.

I am presuming there is a 4ft deep footing around the perimeter of the garage with no insulation. Dealing with the edges the foam insulation and two layers of plywood can add as much as 2 inches of height to the garage floor. If this is the case then the frost will travel down the footing and make the floor cold and thus heat loss. Consult appendix a table a6 3 1 in the 2016 edition for a tabulation of assembly f factors for slab on grade floors based on the arrangement and rated r value of the applied insulation.

Through nearly all of the winter the temperature a few inches above the floor stays in the upper 30s f. Pinning the apron to the slab is just doweling some 4 rebar into the garage slab at each door writes dave richeson. These codes do not require any insulation for slabs that are more than 12 in. Average pir insulation will easily support normal garage loads under a 150mm slab.

Is it worth it to insulate under a concrete slab. Below grade need vertical insulation at the slab perimeter. The f factors for slab on grade floors are defined in standard 90 1. The codes are silent about whether above grade slabs need to be insulated.

Insulate your garage to reduce energy bills and protect your garage against harsh outdoor temperatures. Connecting slab and aprons tying rebar in the slab to sidewalls may not be necessary or even advisable but at least one post suggests that connecting the main floor slab to the aprons at door entrances is a good idea. The back ten feet of the garage structure is an unheated workshop area separated from where the cars park by a framed wall 2x4 and door. 140kpa is the same as 140kn m which is a considerable load.

The math is pretty simple the thicker the concrete floor insulation material the deeper the slab will have. How to insulate a garage floor above a concrete slab. There is no insulation under the slab. The first important thing to pay intention to is the depth of the floor slab.