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XPS tape

Any recommendations on the best tape to use for foamular 250 xps foam for under slab radiant application? I’ve read about some pricy tapes (Siga wigluv, for instance) that might work nicely- but I don’t necessarily need to spend the extra Money on a tape designed for air tightness for wrapping a house since this will only be used to tape the seams for foam laying on the ground. Thanks in advance

Comments

  • JackW
    JackW Member Posts: 197
    When I installed my radiant heating system in my Morton building in 2005 I taped all my 2" pink Styrofoam together with duct tape.
  • Sukhoi29SU
    Sukhoi29SU Member Posts: 77
    I was hoping to get a response like that. I was considering doing the same.
  • ScottSecor
    ScottSecor Member Posts: 547
    I also used a good grade of duct tape when I did mine and a few customers over the years.
  • GroundUp
    GroundUp Member Posts: 1,398
    Do you have a vapor barrier underneath or are you using the foam as a barrier? If the latter, duct tape or anything else not designed to be used as a barrier is not going to be one and "Tyvek tape" is a necessity. If you have poly underneath, use whatever you want or don't tape it at all
  • Sukhoi29SU
    Sukhoi29SU Member Posts: 77
    @GroundUp thanks for the responses , guys. I’ll be using a 15mil stego wrap vapor barrier underneath the xps foam. (I asked about where to put the vapor barrier in a recent thread here... I had received some recs to place it above the foam). Anyway , You make a good point- I cant think of a reason to even tape the seams based on the vapor barrier underneath. I might use a good duct tape - just for peace of mind...
  • mattmia2
    mattmia2 Member Posts: 5,506
    thick, quality packing tape with urethane adhesive may perform the same as the official tyvek tape.
  • rick in Alaska
    rick in Alaska Member Posts: 1,362
    We put the vapor barrier under the foam, and I have never seen anyone tape the foam.
    Rick
  • Ironman
    Ironman Member Posts: 6,868
    edited December 2019
    We've come to the place that we use Creteheat board almost exclusively. It serves as the vapor barrier and insulation and drastically reduces the installation time.
    That being said, if you're gonna use another method, I wouldn't skimp on anything - especially tape. How much would that really save of the total job cost?
    Remember: what you're doing is virtually forever. Once the concrete is poured, you don't get a second shot at it.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Sukhoi29SUGroundUp
  • JackW
    JackW Member Posts: 197
    @rick in Alaska what keeps the concrete from getting under the foam and floating it to the top. Once that happens you would never get it back down.
  • rick in Alaska
    rick in Alaska Member Posts: 1,362
    Well, the foam joints are fairly tight to begin with, and when they start pouring the concrete, the weight of the concrete holds it down. I have never known of anyone who had the foam board float up.
    Rick
    GroundUpJackW