Has anyone used this product? Pros/cons? I'm at least considering it for a gypcrete over pour in a commercial application. The existing building is roughly 5000 square feet, slab on grade with no insulation below. The building is currently heated by a gas fired, 40 year old cast iron boiler with 1 1/4" baseboard. Exposed brick and average windows throughout, gas bills extremely high. I want to couple a new radiant floor with a Triangle Tube boiler, as do the owners. Normally, I would go with 4x8 sheets of XPS like Foamular 400 or the like which could give me an R-value of 5 for 1" and 10 for 2". The Fast Trak looks the same as Creatherms product and has only a 1.7 R-value.