Insulation Under Slab On Ground

A recent caller to the branz helpline asked why the branz house insulation guide does not include examples of a slab on ground floor insulated using either polystyrene under the entire floor slab or a much thicker layer of insulation.

Insulation under slab on ground.

Additional insulation is applied along the edges of the slab because that is a primary surface for heat loss. Suitable product for concrete slab on ground floor. Horizontal insulation placed less than 12 inches below the ground surface or that portion of horizontal insulation extending outward more than 24 inches from the foundation edge should be protected against damage by use of a concrete slab or asphalt paving on the ground surface directly above the insulation or by cementitious board plywood. Kooltherm k3 floorboard is a super high performance fibre free rigid thermoset closed cell phenolic insulation for solid concrete ground based floors.

Slabmate is the new under slab insulation solution for slab on ground construction slabmate has been designed to create a thermal barrier adding to the total insulation of the project. In climate zones 4 and higher it s also a good idea to install some horizontal insulation under a slab on grade. Environmentally friendly slabmate is made here in australia for both commercial and residential projects slabmate is lightweight safe and easy to install and will maintain its r value for the life the building. Depending on the use of the building the slab can then be finished ready for use or receive a screed suitable for a floor finish.

The answer is simply that the thermal performance achieved is essentially the same as only adding insulation under the floor slab for the first 1 2 m from the. As such accurate models continuous r2 0 under slab insulation as improving the home s star rating by a substantial 0 3 and 0 8 stars. Conversely removing this floor insulation from a 7 5 star home will increase total annual energy consumption in active heating and cooling by between maybe 9 and 26. If you want to save money you can install a 4 ft wide band of horizontal r 10 or higher insulation at the perimeter of the slab in a picture frame configuration.

If the insulation is going below the slab the damp proof membrane dpm is laid next followed by the insulation a polythene separating layer and the concrete slab. 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. 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.