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Community and Q&A

Tape for sealing polyiso to a concrete floor?

airfix | Posted in General Questions on

I’ve looked at a lot of the “backyard” tape tests and I don’t see any recommendation for concrete.  The interior of my basement will be lined with 1.5″ of foil faced polyiso.  I’m looking for a recommendation on tape to seal it to the concrete floor in my basement.

I assume Siga Wigluv will do the job but I wondered if there was a more cost effective option than the expensive Siga tapes?

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  1. GBA Editor
    Martin Holladay | | #1

    A good option is Tescon Vana from Pro Clima. That said, I don't know if Tescon Vana is cheaper or more expensive than Siga Wigluv.

  2. Expert Member


    If it is doing to be c0vered, by drywall or a stud wall, consider using a bead of acoustical sealant instead.

  3. Expert Member
    Peter Yost | | #3

    HI Steve -

    There is only one tape I am aware of that adheres to concrete WITHOUT a primer: SIGA Fentrim (

    I have adhered the Pro Clima Tescon Vana to concrete and brick with their primer and it is pretty amazing.


  4. Expert Member
    Michael Maines | | #4

    Steve, I'll second Peter's recommendation to use Siga Fentrim--it's tenacious stuff, and even better for that situation than Wigluv. Pro Clima has several tapes that will work, with a primer, including Tescon Vana, Extoseal Encors, and Contega Solido Exo, each with slightly different properties.

    Fluid-applied sealants are usually less expensive than high-quality tapes. Tremco Acoustical Sealant has a long track record for this sort of thing, but it's nasty stuff. Pro Clima Contega HF is just as good at sealing and staying flexible, but it's low-voc.

  5. airfix | | #5

    I'm not sure I understand using an acoustical sealant for air sealing. It seems like this is just a caulk that doesn't harden. Will it be able to bridge a 1/4 gap between the bottom of the polyiso and the concrete floor?

    With it not hardening is there a danger that during application of the sheet rock and framing over the top of my polyiso that the continuity of the sealant will be compromised more so than if I were to use a tape?

    Talking of sheet rock, what is the best way to seal my sheet rock to the concrete floor? The concrete will be polished and stained as a final finished surface. I'll have baseboards around the bottom of the sheet rock. Should I be taping the sheet rock to the concrete?

    Is acoustic sealant a good way to deal with sealing electrical boxes and other penetrations in my sheet rock?


    1. Expert Member
      BILL WICHERS | | #6

      >Is acoustic sealant a good way to deal with sealing electrical boxes and other penetrations in my sheet rock?<

      That’s what acoustical sealant is for :-) that, and sealing gaps around the perimeter of a soundproof wall. You need a non-hardening sealant since hard materials better transmit sound. I prefer the putty pads myself since they’re cleaner to work with when sealing electrical boxes and the like.

      Acoustical sealant stays gooey over time which means it can stretch and squish and stay stuck and sealed. Normal caulk, after it’s cured, can’t stretch much before it will start to seperate from the surface it’s applied to. Once it seperates, you’ve lost your seal permanently. Normal caulk won’t reseal. Acoustical sealant, because it stays gooey, can somewhat reseal after movement. The gooey nature of the stuff also tends to stay stuck to “bad surfaces” like concrete better.

      The downside is acoustical sealant is messy, nasty stuff to work with and it tends to get on everything while you’re using it.


  6. airfix | | #7

    Thank you Bill

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