Expert: Ted Barnhill (Principal, Design45 LLC) - 11/18/2008

Question
Hello..i have a 23x16 family room that was built over the garage and the floor is a concrete slab..the walls and ceiling are insulated and heat via an extension from house heat are in the room. and there is thin padding and carpet over the concrete floor, however is is still chilly in that room and i do believe the concrete floor is a contributor...any ideas as to how to warm that up...radiant heat under the carpet...better padding and carpet...some sort of reflective insulation under the carpet???suggestions please!!!  Thank

Michael

Answer
Michael,

There are several solutions to your chilly floor problem, depending on your budget.  The first thing you should do is to insulate beneath your concrete slab.  (This assumes that your garage is not heated.  If it is, the concrete floor probably isn't the cause of your chilly room.)  Rigid foam is good choice for your under-slab insulation; provide furring strips so that you can hang a drywall ceiling over the insulation.  

You mentioned radiant floor heat, which is a very comfortable and energy-efficient solution.  However, installation can be costly, especially if you don't have radiant floor heat elsewhere in your home.  Hydronic floor heating (liquid-filled tubes) could be added above your slab in a thin pour, which would raise the level of your floor and possibly cause a threshold step problem.  Electric floor heating can be installed in a thin mat, and while cheaper up front does cost more to operate over time.  In either case, you can install carpet over it, but efficiency goes down.  A tile floor with area rugs is often a great solution.

On the cheaper end, if you have old or thin carpet, thicker pad and carpet will definitely insulate better.  However, the other options above will do far more to create an efficient and comfortable space.

Good luck keeping warm this winter!  Feel free to post any followup questions you may have.  -Ted