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insul-tarp

Unknown
Unknown
in THE MAIN WALL
If all you need is a thermal break, it's more expensive than it needs to be. Use 1/2" Rigid foam.

If you need real insulation, you need more thickness, and Insultarp won't be good enough.

Comments

  • esalen dude
    esalen dude Member Posts: 7
    insul-tarp

    good or bad ? insul-tarp under a 1.5" slab overlay on existing slab with
    5/8"o.d. pex radiant tubing reinforced with 1/4" steel grid. ??
  • [Deleted User]
    [Deleted User] Posts: 1,160
    Time will tell...

    I'm testing it and 5 other different types of insulation below a snowmelt system. I've been recording data hourly for 3 weeks now, but it hasn't snowed yet....

    Supposed to snow like mad this weekend. Provided the prognosticators are not wrong, should have a plethora of performance data come next week.

    Stand by...

    ME
  • Ron Schroeder
    Ron Schroeder Member Posts: 995


    So far I haven't seen ANY insulation less than 3/4" thick that is worth anything as under slab insulation.
  • jerry scharf_3
    jerry scharf_3 Member Posts: 419
    something but not much

    You've got a thin pour on top of an existing slab. You almost certainly want some form of crack isolation membrane between the two layers. If you want some insulation, you'll get what you allow for the thickness of the insulation. Given the thin nature of the pour, my guess is you don't want to give up much space to insulation thickness. Insultarp would do something but not magic, a WAG of R1, It would be quite easy since you just use it like any other isolation membrane. I would expect xps foam baord to outperform insultarp, but we are all awaiting Mark's numbers.

    Worth the cost of it vs. a simple membrane? Worth the cost of it vs. a membrane and 1/4 or 1/2" xps? Hard to say.

    jerry
  • esalen dude
    esalen dude Member Posts: 7
    insulation over existing slab in a overlay situation

    wouldn't any insulation over an existing slab create a greater probability for cracks, or hollow pockets in a thin overlay (1.5") ? I would think that to bond the overlay to the main slab would be important, and to only use perimeter insulation in a pour-over of this kind. How far below the main slab (4") do you think the heat would penetrate ?
  • Unknown
    Unknown


    I haven't heard this to be a problem, but then I'm not a concrete expert.

    The heat will go where the heat will go. In the residential world, you usually must insulate the entire the slab or close to it at least. If the existing slab is not insulated, then you *probably* need a thermal break. If you can instead insulate the perimeter edges of the entire assembly, then perhaps it could be negotiated depending on your site conditions. If that ground gets saturated, all bets are off and you need continuous insulation.
  • esalen dude
    esalen dude Member Posts: 7
    the heat will go where? up

    The heat will go where the heat will go. Isn't it common knowledge that that is up? yes in convection but what about conduction? and are you saying that with water table rise it adds moisture to the slab increasing conduction of heat downward ?
  • Unknown
    Unknown


    Water table brings a very effective conductive heat loss (water) in contact with the slab. I have seen slabs that actually could not maintain temperature because of this heat loss during wet seasons.

    Heat does not rise. Hot air rises. Heat travels to cold, regardless of direction.
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