Air sealing transition from exterior to interior
Hill_Builder
| Posted in General Questions on
We are climate zone 5 with an unconditioned space above the house with zip walls and Siga Majrex on the ceiling. We want continuity on air sealing from the zip wall to the Siga majrex on the ceiling by draping and taping a 16” strip of Siga between the top plate. Our contractor says not necessary. We are on a windy hill, but he will do it if we want. We are not trying to do a net zero house, but are trying to seal it up as much as possible. Should we compromise this part or not?
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Replies
Hill Builder,
You need a continuous air-barrier. How is your builder suggesting you achieve that?
You may find this recent discussui0n useful: https://www.greenbuildingadvisor.com/question/air-barrier-continuity-at-sheathing-top-plate-ceiling-transition
He said our house is going to be super tight and to not to worry about it. Then when we said we really wanted to drape the Siga strip, he said would just lay it up against the back side of the drywall and that would work. He questioned that we are putting an inside product (Siga) outside when we tape it to the Zip sheathing. He continued with the fact we are over thinking it and then added he was not sure the framers will any of this. We are to meet up with him this week and in the mean time trying to find the least amount of work for him to get a continuous air barrier that works for us.
Thank you for the link, we will read over it to see if there are any ideas there.
We are at this exact stage in our project. I'm owner/building my home so more involved than others. But, I just hopped up on a ladder and attached Siga Majvest 500 to the top plate (it's made for this) this morning. The framers will put the rafters/trusses on top of this as they normally do and I'll be able to connect the outside and the inside. Our house is pretty simple, but it's an easy detail that took me an hour. So -- if framers are upset about it, have the GC do it and tell him you can pay him for a couple hours of his time. Or if it's allowed in your agreement, just jump in and do it yourself. I spent a long time trying to figure out this detail but this project makes it easy.