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staple up insulation

hot_rod
hot_rod Member Posts: 21,793
In my shop for 6 years now. I did contact the pex manufacturers for approval. I have 3 different brands of foam sprayed in my shop against two different brands of barrier pex.

I think the UV is doing more harm than the foam insulation in areas where the pex is exposed ;0

hot rod
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream

Comments

  • kevin coppinger_4
    kevin coppinger_4 Member Posts: 2,124
    I have a large...

    staple up job upcomming...1/2" pex w/ joist trac plates....insulation that is being talked about is spray foam.... do i just let him dirctly apply to the plates or should I go w/ a product to isolate it first...They had a reflective cardboard to put in the joist I saw at one timety,kpc

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  • hot_rod
    hot_rod Member Posts: 21,793
    temperature rating

    check with the foam installer regarding the temperature you are planning to run. I have 4 jobs running with foam sprayed against the pex and plates. All is well.

    The foam does an excellent job of sealing the rim joist loss and air gaps.

    Skip the reflective cardboard stuff, you don't need it. Even if you go with fiberglass batts instead of foam.

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • scrook_2
    scrook_2 Member Posts: 610


    Kevin..........I am a Corbond spray foam contractor. My product is a closed cell polyurethane spray foam. My foam is very dense as opposed to an open cell foam which is nowhere as dense as closed cell. If I was doing the spray job, I would insist that the joist trac plates be totally sealed against the sides of the floor beams. If my foam should find its way into the space between the trac and the tubing, it would be doing more harm than good. If the pex gets covered by my foam,it will generate no heat at all. If I were you,I would tell the contractor to somehow seal the tracs as to not allow any of the foam to seep into the area underneath the joist tracs. Perhaps duct tape to seal the tracs on the sides of the floor beams. Feel free to e-mail me if you have any questions that I might be able to answer for you.
  • MechTech_2
    MechTech_2 Member Posts: 84
    Insulation

    Has anyone seen PEX fail (chemical reaction) that has been covered in a spray foam product. I haven't seen it yet, but I'm a little curious.
  • hot_rod
    hot_rod Member Posts: 21,793
    Interesting thoughts

    and valid concerns Billy.

    I doubt duct tape would stick to the plates or floor very well or for very long.

    If you are going to use extruded transfer plates the tube to plate connection will be a tight fit. Usually a mallet or palm nailer is used to install the tube. I doubt the foam could penetrate and upset that tight connection.

    Foam on the bottom side of the pex would be a good thing, the more the better.

    The plate to subfloor connection is critical. They should be screwed tightly to the subfloor or the conduction transfer is non existent, be it an air gap or a thin foam barrier.

    Check out the last pic in this attachment. notice the two areas where I pulled the transfer plates away from the subfloor to crimp into the tube. I forgot to replace the attachment screws and the conduction transfer went away.

    if you do go with a cardboard or other layer be sure it has an attachment that will last. Foam blowers around here refuse to spray against that foam sheet with aluminumin film that many metal building installers are trying to use under the metal roof panels. The lack of r value in that 1/2" foam becomes quite clear when the temperature drops and the gas meter starts spinning. It's a hard detail to correct after the building is up. spray foam could be an excellent fix for that inadequate insuation board.

    hot rod
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
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