Insulating Under A Concrete Slab Floor

In addition to offering insulation and energy savings the plywood subfloor described here can provide the perfect foundation for finish flooring such as carpeting adding warmth in look as.

Insulating under a concrete slab floor.

How to install insulation below a floor slab with kingspan kooltherm k103 floorboard. If you re pouring up against your foundation walls insulate between the slab and the walls. Slabs that include embedded hydronic tubing for radiant heat always need a continuous layer of horizontal insulation under the entire slab. Designers generally insulate both directly under the slab and around the perimeter as well.

Once again a thinner insulation such as vacuum insulation may be a more cost effective or more practical option in the long run. Insulating the slab using rigid foam insulation around the perimeter of the slab to minimize heat loss seems like an obvious step but whether to place insulation under the slab is another story. The reflectix concrete slab insulation is an innovative easy to handle product that increases the energy efficiency of radiant floor and snow melt systems under concrete. Continuous insulation is applied directly to the underside of the slab and extends inward horizontally from the perimeter for the distance specified or continuous insulation is applied downward from the top of the slab and then extends horizontally to the interior or the exterior from the perimeter for the distance specified.

That decision may hinge on whether the slab is heated but there s no agreement on what building codes require if anything. How you insulate under the slab depends upon the severity of your winters. In cold climates it is advisable to use a minimum of 2 inches of extruded polystyrene under the slab. Insulating a concrete floor can save you money on your heating bill making an attached garage or basement warmer and by extension the rest of your house.

Many increase the under slab insulating foam board thickness to 3 or 4 inches at the outer 2 to 4 feet of the slab. For a cleaner looking installation cut the top edge of the foam board at a 45 degree angle so the concrete will flow all the way to the foundation wall and hide the foam. If your slab is heated it s a good idea to increase the r value of the vertical and the horizontal insulation to at least r 20. The foil within the product acts to spread out the heat signature of the heating coils.