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Installing Radiant in my garage, I have a bunch of ? head is spinning

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Comments

  • RobG
    RobG Member Posts: 1,850
    finding Insulation

    If your plumbing suppliers don't carry rigid polystyrene insulation, the big box stores do. As well, any construction supply house or concrete supply house should have it.

    Rob
  • JoeG
    JoeG Member Posts: 88
    I can get it

    The Blue board is easy to find, I Have used it before, I priced it out and with my Discount it'll still be about $976.00 After taxes.
  • RobG
    RobG Member Posts: 1,850
    EPS

    Well, as you said earlier, you can get insul tarp for $500 or XPS for $976. It breaksdown like this:

    Insultarp, R-.05 = $500.00

    XPS, R-10 = $976.00

    You do the math.

    Rob
  • Gordy
    Gordy Member Posts: 9,546
    Blue or pink

    Should note that there is 150 psi, and 250 psi xps. 40 bucks a sheet sounds steep to me with a discount for 2"
  • Gordy
    Gordy Member Posts: 9,546
    Eps, xps

    Eps expanded polystyrene is only r3.8 per inch not recommended for under slab. Xps expanded polystyrene is r5.0 per inch. 150 psi would be fine for an average car type garage with a 5" slab. They make all the way up to 600 psi in the pink.
  • JoeG
    JoeG Member Posts: 88
    Price

    Home depot if my Math is right is about the same price.
  • JoeG
    JoeG Member Posts: 88
    6 Inch

    Also the slab is going to be 6 Inch and I think a foot on the out wall area.
  • Zman
    Zman Member Posts: 7,611
    In my area..

    In my area the standard slab thickness is 5" unreinforced or 4" reinforced. You must have some interesting soils in your area. Be super careful that your tubing does not end up at the bottom. The concrete guys will not pull it up without you prodding them.

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • SWEI
    SWEI Member Posts: 7,356
    compressive strangth

    150 and 250 PSI both sound wrong.  Foamular 150 has a compressive strength of 15 PSI, F-250 is 25 PSI.  I mostly use Dow Highload 40, which is also sold in 60 and 100 PSI versions but almost nobody stocks them.
  • JoeG
    JoeG Member Posts: 88
    Code

    I believe code is at least 4 Inch thick here, I know that it is stone, then insulation, then rebar or some sort of wire then the tubes.  How to you hold it up so it doesn't settle?
  • Zman
    Zman Member Posts: 7,611
    Rebar

    If you use wire mesh you pretty much have to be sure the guys pouring the concrete is pulling it up as they go. Te better method is to us is to use #3 rebar and put it on chairs. Not only will it heat better, the rebar or mesh will actually do it's intended job (making the concrete stronger.

    Carl
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • zacmobile
    zacmobile Member Posts: 211
    perimeter insulation

    And please insulate the perimeter of the slab, many (I would even venture most) people neglect to do this and it is a major source of heat loss that will make your supposedly efficient radiant floor system much less so. Don't forget about the bay doors too, no heated concrete should be exposed to the outside, i've seen different details for this but a good way i've seen done is to have a break of 2" styrofoam with an aluminium or steel plate on top across the threshold.
  • JoeG
    JoeG Member Posts: 88
    I hope

    I hope it is done right, Ill be over seeing them, I want a nice working efficent system that does what I need it to do.
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