Radiant heat in a concrete pier foundation????

[2zwudz]

  I am beginning to build my 16x24 cabin on concrete piers and was thinking about installing a radiant floor heat system between the floor joices and insulating under that to hold the heat.  Has anyone had any luck having radiant heat under a pier foundation?
Thanks Mark

[ScottA]

We tried that in colorado a few years back and didn't have much luck. Without the thermal mass to soak up the heat it just doen't work right. What you can do is tack the tubes to the floor and then pour lightweight concrete over them. That does work.

Scott

[2zwudz]

    What is "lightweight concrete" and how thick does it need to be.  Will lightweight concrete be too heavy for a 8" concrete pier foundation using the Bigfoot forms?
Mark

[ScottA]

The way I saw it done was to double the bottom plate of the wall and use that as the form for the mud. I belive lightweight concrete is aerated and made with lightweight aggrigates. A Google search should turn up some info on it. http://www.elastizell.com/floors.html

Scott

[ScottA]

Near as I can tell it will add about 13-15 lbs. per sq. ft. of dead load. You'll need to determine what your floor system can hold.

Scott