THE BEST PLACE TO INSULATE  A CONCRETE WALL IS ON THE OUTSIDE OF IT. THIS CAUSES THE CONCRETE TO BECOME PART OF THE THERMAL MASS AND ADDS TO THE COMFORT AND
EFFICIENCY OF THE HEATING SYSTEM.  WHEN THE INSULATION IS PLACED ON THE INSIDE OF THE WALL IT CAUSES THE CONCRETE TO ACT AS A HEAT SINK.

PRODUCTS CONTAINING  FOIL OR PRODUCTS USING EXPANDED POLYETHYLENE FOAM
SHOULD NEVER BE INSTALLED UNDER SLABS!!
USING TWO INCHES OR MORE OF HIGH DENSITY FOAM BOARD IS THE ONLY INSULATION UNDER A SLAB THAT IS WORTH ANYTHING IN MY ESTIMATION!!
Products that in my estimation are worthless under a slab are RadiantGUARD®, Slab-Shield™,
Insul-Tarp™,  Reflectix®,  TVM rFOIL™, Ultra C B F™,  Radiant GUARD™

The performance of radiant barriers in wall and roof assemblies can not be compared to underslab applications. If a distributor or manufacturer intentionally or unintentionally has lead you to believe this conclusion, contact the Federal Trade Commission, toll-free.    1-877-(382-4357)

MORE SLAB INSULATION