Rigid Insulation Under Basement Slab

Reduces energy loss between ground and concrete slab reduces potential for condensation and moisture damage high compressive resistance can sustain heavy loads without damage.

Rigid insulation under basement slab.

Dupont styrofoam brand extruded polystyrene foam insulation is an ideal solution for under slab installations offering the following advantages. 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. When slab insulation is provided a sheet polyethylene vapor barrier should be located over the rigid insulation and in direct contact with the concrete slab. Place a 1 inch layer of 4 x8 extruded polystyrene foam board over the gravel covering the entire floor area.

View the owens corning basement and crawlspace insulation 48 78 48 78. As the slab will only be able to dry upward the slab should be allowed to dry before finishes are applied. 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 pavement or by not less than 10 inches of soil. You want to create a tight insulation layer.

If the foundation is on frost susceptible soils install a layer of impermeable insulation horizontally in the soil at a slope ratio of 1 5 for at least 1 m 3 ft. Get free shipping on qualified under slab foam board insulation or buy online pick up in store today in the building materials department. A careful evaluation of these materials performance attributes against the project s needs can dramatically shrink labor and material costs. Tape the joints between the boards with builder s tape.

Insulation is applied to houses with slab on grade foundations exactly as you would insulate the outside of a full basement see section 6 1 insulating the basement from the outside. 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. Evenly spread the base gravel under the basement slab keeping it 1 inch lower than the conventional method.