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Adhesive and ignition barrier for unfaced polyiso?

agurkas | Posted in Green Products and Materials on

I got couple pallets of polyiso from an insulation recycler. It is NRG Insulation, 1.5″ stuff. But it isn’t foil-faced. Will be installing those in my basement with poured concrete walls.

Two questions:

1. What is the best adhesive (I can hopefully get at Home Depot or Amazon) to glue those polyiso panels to the basement wall, and how much of it do I use per panel?

2. Since it is not foil-faced polyiso, can I use FSK paper for an ignition barrier or is there another alternative, besides drywall?

Thanks!

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Apollo,
    Any foam-compatible construction adhesive should work. (Read the label before you buy the adhesive.)

    I would use beads of insulation about 6 inches apart, and would apply pressure until the adhesive sets. (One way to apply pressure is to use scraps of plywood or OSB, held in place by long 2-bys that are wedged against the opposite wall.)

    Most building codes require rigid foam installed in a basement or crawl space to be protected with a layer of gypsum wallboard. If you have any doubts on this issue, contact your local building department.

  2. agurkas | | #2

    Martin, unfortunately I live in small town where we have one inspector for everything and he is part time for 8 hours per week and out doing inspections. So getting a chance to talk to him is nill. Heck, he is yet to come inspect gas boiler install and it has been a month.

    That said, here are two follow-up questions:
    1. Polyiso I got was used in a commercial building and is the kind that has some kind of fiberglass-looking sheathing on it. I wonder if that is fire-rated. I am not really doing this to appease code compliance, but rather safety of my family.
    2. Are there any particular adhesives you have seen work better than others? I have used your recommended 3M Allweather tape to seal up casing of the replacement windows I had installed and it was best recommendation so far I got on this site. I saw on some threads Locktite PL300 mentioned for poured cement and cinderblock walls.
    3. If I only have gypsum route. Is the SHEETROCK Mold Tough is the product that would work? http://www.homedepot.com/p/SHEETROCK-UltraLight-Mold-Tough-1-2-in-x-4-ft-x-8-ft-Gypsum-Board-14302111708/203768542

    Thanks for the help!

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