A significant contributor to building air leakage is from exterior walls. We have had consistent success with these three methods to address air leakage through walls, which each rely on rigid sheathing as a stable substrate with long-term integrity:
Tape the exterior seams and edges of the plywood sheathing for continuity (in addition to a separate loose water resistant barrier), or
Install a fully-adhered weather resistant barrier (WRB) sheet good for both air tightness and bulk water management, or
Install a fluid-applied WRB for both air tightness and bulk water management.
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