How to Hang Airtight Drywall on Exterior Walls
You'll need caulk, adhesive, and foam seal for this air-sealing job.
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Before hanging the walls, cut back all of the canned foam applied to the ceiling perimeter, any obstructions around windows, and if not done on the pre-construction walk-through, seal all of the gaps between framing members.
Again, the face of the studs get a thick bead of adhesive. Windows get the royal treatment. Use both latex caulk and polyurethane construction adhesive.
Place the left edge of the sheet into the corner and then lay the rest of it flat against the framing, caulk, and adhesive.
After the cutouts are made for the boxes, seal the drywall opening to the edge of the box opening. First, brush out the dust so that the caulk can stick. Then apply a generous bead of caulk around the perimeter of the box. Smear it in with your finger to make sure the opening is sealed.
It is not just windows and electrical boxes that can make a wall tricky. This big conduit running from the electrical service panel outside to the breaker panel inside presents a bit if an obstacle. To best treat this, we removed the fastening brackets so that we can slide a sheet of drywall behind it.
After the drywall is sealed up, the conduit can be boxed out. Don’t box out the chase before the drywall because this introduces long cracks in an otherwise continuous plane.