insulating concrete floor for radiant ht
I am installing radiant heat in the concrete basement floor of a new building. The building has a walk out basement. The insulation, tubing, and forms are set to pour the floor on Tuesday morning. I have insulated under the floor and around the perimeter with 2″ rigid foam insulation. However, there is a problem with insulating the floor on the walk out basement wall. My concrete contractor wants to pour the concrete for the floor directly onto the frost wall on that end of the building. Structurally this is the right answer, but this also connects the floor thermally into the concrete of the frost walls which are not insulated and the rest of the foundation.
The walk out end wall will be framed on the floor, so a good foundation (without compression) is necessary.
Is there a material that I can use to insulate between the top of the frost wall and the floor which will support the load for the gable end wall on a single story building and not compress over time?
Thanks for your help.