How to warm up a cold concrete floor

April 24, 1981

Q. My two-story home built on a concrete floor has about 8 inches of slab which is exposed to the elements just above grade. The winter temperature of the concrete slab is so low that it negates the effects of the heater for the first story. I would like to insulate the 8-inch exposed outside slab area. Is this feasible? If so, what are your recommendations as to material and technique? Fred Kolstrom Toms River, N.J.

A. By all means, insulate not only the perimeter of the exposed slab aboveground but below grade as well.Such thermal insulation is common practice in new buildings.In some states it is mandatory in new construction.

Your city or county building inspector can give you good advice on local code requirements, materials, and techniques. A telephone call should suffice.

Likely, the material used will be rigid and capable of enduring the weather as well as the dampness below grade.

Obtain the insulation material from an insulation company or building-supply house. Watch for the R-rating of theinsulation. The higher the R-humber the more effective is its insulation value.