Air can pass through interior partition walls, make its way to an outside wall and escape. To prevent this, seal the intersection of interior and exterior walls. This is most easily accomplished after framing is completed and the shell is insulated.
The sealant can be drywall adhesive or a compressible gasket. If you choose drywall adhesive be sure to lay a continuous bead of adhesive. Gaskets could be installed any time before the drywall goes up. For both materials, the seal should run from the subfloor to the top of the top plate.
This seal can be applied to the backer stud in the exterior wall or to the last stud in the partition wall. (Sealants must also be applied to plumbing and wiring penetrations through the last stud.)
