Air sealing at top plate
I am owner-builder on an extensive remodel where the entire above-grade structure above the floor joists is being replaced. After extensive planning and research prior to start of construction, I was off to a good start on air-sealing details with EPDM gaskets under the sill plates, and acoustical sealant on-hand for sealing sheathing to the sill and top plates. However as I feared, at some point the framers forgot to apply the acoustical sealant on some large sections of wall, and now I’m uncertain exactly how to air-seal at the top and bottom of the walls.
I am considering some sort of self-adhered flashing at the bottom to seal the sheathing to the foundation which I can seal the WRB to. I can’t think of any way however to effectively seal the top of the wall and make it continuous from the sheathing to the air-tight drywall in the ceiling. I think switching to an unvented roof and spray foam might be a solution, but that would really strain the budget and therefore may not be an option. Is there another way to make the air-barrier continuous with the already installed sheathing? Would caulking or consumer spray foam from the inside provide enough of an air-seal? Am I overthinking this?
Any advice would be greatly appreciated!
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