Insulated Floating Slab Foundation

In cold climates most slab on grade foundations include perimeter stemwalls or frost walls that extend 3 ft.

Insulated floating slab foundation.

The area between the stemwalls is usually filled with compacted gravel to support the slab. Because they are easier to insulate slab foundations with stemwalls are preferable to monolithic slabs. The result is a very comfortable and energy efficient basement with no thermal bridging and reduced risk of mold. A floating slab is the basic foundation structure used for buildings that do not have basements garages sheds barns and even some homes in high water table or coastal areas.

Alternatively a basement can be constructed by beginning with an insulated raft slab followed by an icf foundation wall. Insulated floating subfloor over slabless slab. This is for a house with an r 11 insulated slab. This provides a continuous layer of insulation separating the concrete from the ground.

So let s look at the mechanics of actually insulated the slab. As a percentage of heat loss the floor went way down compared to the un insulated slab house. Now look at this chart with a house with similar specs for walls roof but it has an r 11 perimeter insulated slab. Using conventional readily available materials fpsf is an alternative to stem wall and floating slab foundations however it is most suitable for slab on grade homes on sites with moderate to low sloping grades.

Watch this animation for the proper procedure to insulate a monolithic slab.