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Insulation ?

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RayH
RayH Member Posts: 98
in Radiant Heating
I'm installing radiant heat in a basement slab. What is the prefered insulation to use ? Thank, Ray

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  • Snowmelt
    Snowmelt Member Posts: 1,415
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    im thinking anything with a .5 r value or better
  • Zman
    Zman Member Posts: 7,569
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    You absolutely don't want any product that claims reflective properties like "double bubble".

    I would recommend any closed cell product with a weight rating of 25 psi or better. Dow Blue Board or field applied sprays are commonly used.

    The energy code should call out the required R-value for your zone. R-10 (2") is a good place to start.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Rich_49
  • hot_rod
    hot_rod Member Posts: 22,139
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    I think some codes now require 2" minimum. About 5 per inch R for the blue and pink foam boards, and they are intended for under slab use.

    Or the CreteHeat products with the knobs to hold down he tube, you get a vapor barrier included with those products.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • GroundUp
    GroundUp Member Posts: 1,907
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    2" XPS is R10 and what I use as a minimum on all installations. As was mentioned. That "double bubble" crap is a joke at best
  • nibs
    nibs Member Posts: 511
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    Ray, am a newbie so do not know if you are DIY or pro.
    If it is DIY you can sometimes find Used Dow Roof mate EPS that a roofer has taken off a flat roof, it is 4" thick stepped and has a good PSI, you can walk on it with boots and not leave heel marks.
    You can lay it on a vapor barrier, tape the joins and have R20 for a lot less than the big box hardware stores. You might check with your local inspector to see if he will accept it. He should it is excellent closed cell material.
  • nibs
    nibs Member Posts: 511
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    Dennis, why would Hydrofoam have a different response to the movement of heat, than say XPS, or other closed cell foam?
    Trying to learn as much as possible about insulation thank you.
  • Gordy
    Gordy Member Posts: 9,546
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    ^ it doesn’t. At least not more so than any other similar product as hydrofoam.

    As a matter of fact a tube fully encompassed by the concrete is more effective at heat dispersal/ exchange than tube laying on the foam inslation covered in concrete. A fraction of the tube unless it floats off the foam during pouring is against the insulation medium.
    Zman
  • RayH
    RayH Member Posts: 98
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    Has anyone ever used Rapid Grid for Viega ?

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