A double-stud wall buys extraordinary insulation depth with ordinary lumber — two independent frames with a wide, fully insulated gap between them. The trade-off is moisture sensitivity at the cold outer face, which is why this system leans hard on a smart vapor retarder at the interior, an airtight layer that is genuinely continuous, and drying capacity designed in both directions.
Deep walls are unforgiving of improvisation. Treat this documentation as the general logic, and put your actual section in front of your design professional of record.
Two frames, one wide insulated gap — dense, void-free installation is the craft.
A smart vapor retarder handling both airtightness and seasonal vapor flow.
Sheathing, WRB, and a ventilated gap that give the wall its drying path outward.
At this airtightness level, HRV is part of the assembly conversation, not an accessory.
Send the section — double-stud details are exactly what the desk likes to review.
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