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polyken 629 sheathing tape

Bluegoose68 | Posted in General Questions on

I’m looking for a tape to use to seal the seams of some interior OSB ceiling sheathing.  (Air barrier for interior OSB).
My local building supply store carries a tape called Polyken 629 Seam & Seal Contractor Grade Sheathing Tape.  A 50 meter roll is $22.  Price is certainly reasonable but I’m wondering about the quality of this tape.  I’ll attach their data sheet below but the adhesive is acrylic and the backing is BOPP Film (whatever that means.)  
Does anyone have any experience with this tape or can anyone recommend it?

My other option is to try and leave an 1/8″ gap between the panels and then seal the gap with caulk.  I believe the tape would be much quicker but if it doesn’t stick well, it won’t be good long term.

Appreciate any help or advice.  Have a good day.

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  1. Chris_in_NC | | #1

    BOPP is Biaxially Oriented Polypropylene, which just refers to how the tape is made; the film is stretched in two directions so the polymer chains align in two directions for better film strength. Nice bit of trivia, but likely not especially important when comparing tapes.

    Based on the datasheet specs (BOPP, 3 mil film, acrylic adhesive), 629 sounds similar to some other housewrap/seam tapes like 3M 8087. That's a class of thin tapes with a thin adhesive layer.
    If you want a very aggressive tape with known characteristics on bare OSB, something like ZIP tape or 3M 8067 will work well but at a higher cost. LP Weatherlogic and GP Forcefield (premium/yellow) system tapes would also likely work well, but seem to be less commonly available. The ForceField standard (gray) tape is a thinner tape and rather cheap, but not sure how it would adhere to bare OSB (not sure of adhesive thickness). All of those have modified acrylic adhesives as far as I know.

    I'm not sure if there is much difference in the type of acrylic adhesive between 8067 and 8087 for example, but the difference in the thickness of adhesive can make a big difference when trying to adhere to something rough like OSB instead of something smoother like housewrap or sheet foam, etc.

    Because this is an interior application for air sealing, you don't really have to worry about many of the difficult exterior conditions like UV exposure, wet adhesion, broad temperature cycling, etc., so it's theoretically a fairly pampered life for a seam tape.

    Liquid flashing products like Prosoco Fast Flash are a good alternative to tape, but then VOCs may (or may not) be an issue depending on where you are in your construction process. Tape is still likely the fastest/cheapest/easiest option though unless you have complex geometry that would be better suited to liquid products. If you have simple geometry and transitions, tape it. No different than the considerations when air sealing exterior sheathing.

    1. Bluegoose68 | | #2

      Thank you for the very thorough reply. Sounds like this Polyken 629 tape is made of the right material, but maybe not enough of the good stuff (adhesive) to be a really top quality tape. Considering the price, that seems likely.
      I'm still undecided on using tape vs caulk. If I can convince my builder to leave a small gap between panels (I believe most OSB is undersized by 1/8"), I think caulking and painting both the OSB and the caulk will look best. I believe the caulk would also be an effective air barrier.
      The beauty of this particular tape (compared to the 3M or ZIP) is that this tape is plain white on the exterior side. I don't mind spending the money for a premium tape, but I'm not excited about the 3M or ZIP logo showing up every 10" (and I doubt I can paint over those tapes).
      I looked up the Prosoco Fast Flash product you mentioned but it seems like their Joint and Seam Sealer product would be more applicable. Are both products OK for this application?

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