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Radiant Slab Near Granite Ledge

Has anyone had any experience installing Radiant in a slab, where Granite ledge is nearby? I have a job where they had to blast ledge, and it will be close to the Radiant, are there any special insulation requirements? Does anyone have any experience with a system like this consuming a lot of energy?
Thanks, Bob Gagnon
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  • kcopp
    kcopp Member Posts: 3,772
    I looked at a project one time where this was the case but the HO balked at the cost. Best I can figure it to make sure you have a thermal break in between the slab and the ledge.
    It would have to be a higher operational cost over a traditional radiant slab....
  • Jamie Hall
    Jamie Hall Member Posts: 16,332
    I've had a couple of situations where a solar heat store slab was close to ledge. I put in another 2 inches of foam insulation on top of a sand cushion below the slab. Seemed to be OK... Made sure the sand couldn't get wet! Frost walls on those went down to the rock, but the slab was insulated from the walls, too.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England