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Community and Q&A

Stemwall to sheathing air seal

joenorm | Posted in General Questions on

Is there an alternative to what seems like the one tape product people are recommending here for the concrete to sheathing transition. I think its a Siga product but I’m short on time to get that product shipped (not to mention expense).

Would a high quality caulk do the trick for an air seal? Maybe not as good a choice but at least be worth my time doing it?


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  1. Expert Member
    Akos | | #1

    I've had good luck with WP200 with concrete to wood. Make sure you prime and then lap your WRB over it.

    For a belt and suspenders, a heavy bead of caulk under the WP200 doesn't hurt.

  2. Expert Member
    Michael Maines | | #2

    On one project I was involved with the contractor didn't want to use European tape, so in place of a sill sealer he bedded Vycor in PL Premium polyurethane construction adhesive, then used another bead to seal the mudsill to the Vycor, then sealed the sheathing to the Vycor with 3m 8067 All Weather Flashing Tape, which should be available at most lumberyards. I think Siga Fentrim would have been faster, easier and cheaper, but they got a good blower door test.

    Siga Fentrim ships quickly, with free shipping over $200: You can apply it after the house is framed.

    Another tape made for this location is ProtectoWrap Triple Guard: Your local lumberyard might even carry it. It's a decent product but not as sticky as Fentrim, and needs to be installed when the mudsill goes down.

  3. joenorm | | #3

    Thanks. And a follow-up......... I have a vented crawl space, does that make this whole topic moot for me? Or am I still trying to prevent air from entering wall from the exterior?

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