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radiant floor insulation

bill_42
bill_42 Member Posts: 2
in THE MAIN WALL
I am installing a radiant floor system in my new house in Montana. We have a crawl space and are stapling the pex pipe to the bottom of the floor.We also installed the bubble insulation in each joist space with a 4 inch gap between the floor and the insulation. Will additional insulation below the bubble insulation be needed and how much?

Comments

  • kevin coppinger_4
    kevin coppinger_4 Member Posts: 2,124
    bag the bubble...

    when the heatloss was done what was figured for the insulation R factor? put down a good vapor barrier on the floor of the crawlspace and use fiberglass insulation w/ the kraft up towards the floor....kpc

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  • Constantin
    Constantin Member Posts: 3,796
    IMHO, yes.

    Bubble-foil is cute, but not very effective against convection or conduction. Plus, those staple-up pipes are going to get mighty hot as they try to warm the floors above.

    I'd supplment that radiant barrier with something suitable like 2" thick XPS (that'll give you R10) which will work well in a crawlspace (it doesn't absorb moisture).

    Naturally, the thicker the XPS, the better. Use long, thin screws and very wide washers when attaching it to the joists above. Then seal all the joints between XPS panels with closed-cell polyurethane foam ("good stuff" or eqv.). Good luck.
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