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Community and Q&A

Tape for sealing polyiso sheets?

NICK KEENAN | Posted in Energy Efficiency and Durability on

Curious what kind of tape people use to get an air-tight seal on polyiso sheet insulation. My inclination is to use Tyvek tape but tell me your thoughts.


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  1. Expert Member
  2. Expert Member
    NICK KEENAN | | #2


    For the curious, here's the money quote from the article:
    "Foil-faced polyisocyanurate. Foil-faced polyiso is very easy to tape; almost any decent tape will work."

    Tyvek tape it is for me.

  3. Expert Member
    Michael Maines | | #3

    For situations where the insulation will be hidden, such as continuous exterior insulation, I like using plastic tape with acrylic adhesive--it sticks well and can stretch; polyiso tends to shrink as it ages and plastic tape will stretch, while foil tape does not. I have not seen any studies on this, it's just a hunch that it could be a problem.

    For basement interior insulation, I often spec white foil-faced Thermax with all-white foil tape, for a neat finished appearance. I have not found an all-white plastic tape.

    1. Expert Member
      NICK KEENAN | | #4

      Here is an all-white plastic tape that I like:

  4. Expert Member
    Michael Maines | | #5

    Thanks DC! I have spent a lot of time looking for a tape like this, even on 3M's website.

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