Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

What is the best insulation for under slab radiant?

wcm19 Member Posts: 1
I'm looking at INSUL-TARP, THE BARRIER and ridgid polystyrene.


  • Devan
    Devan Member Posts: 138

    extruded polystyrene is what I prefer.
  • NRT_Rob
    NRT_Rob Member Posts: 1,013
    2" of rigid foam

    extruded or expanded polystyrene of appropriate compressive strength.

    Insultarp is junk. it isn't even really insulation. NEVER use it, and anyone selling it either does not understand what they are selling, or doesn't care.

    the barrier is actually foam, so that's good, but it's not as thick as you want.
    Rob Brown
    Designer for Rockport Mechanical
    in beautiful Rockport Maine.
This discussion has been closed.