Hi all I recently purchased a commercial building in RI, that has a poured concrete foundation and block construction. It is about 2200 sq. ft.(30' x 74') There is a full basement accessed by stairs down and also a drive in garage door. The ceiling of the basement(or the floor of the upstairs) is made from what I believe are called flexicore panels. They are about two feet wide and span the width of the building which is 30 ft. They each have 3, 5" diameter hollow areas running the length of the panel(30'). There is about a 1.5" poured concrete floor on top of the flexicore. The space is currently heated with a couple of gas fired unit heaters hung from the ceiling. I had an energy auditor in today to discuss insulation, weatherproofing and heating issues. He suggested it might be possible to run radiant tubing thru these hollow spaces in the flexicore floor to heat the space. I was wondering if anyone had any thoughts on this concept, or possibly other suggestions. I am a woodworker, so the blowing unit heaters are not ideal. Thanks in advance.

Have some experience with the flexi. Purchased it from the plant in R.I. Built a pier with the 8" (3 three hole) and a building on the pier with 10" (2 hole) (and flood proofed the walls with 6" (4 hole)). I got the idea from my cousin Rob who built his house with the 8" on the first floor. He had them cast holes in the middle of the run (with styrofoam) and he put a manifold down the middle and has the air coming out the end of the flexi to heat the first floor of his home. You can cut holes in the flexi over or under the holes but must not cut on the web as there are prestressed cables in the bottom. Best to call flexicore for the details. They were very helpfull as I requested prestressed cable top and bottom and they engineered just what I needed. Hope that helps!