Superinsulated Double-Stud Wall and Cold Sheathing
Just want to thank the community for being the continual wealth of knowledge that it is.
In examining super insulated walls without exterior insulation, cold sheathing keeps coming up as a concern. less energy makes it through the insulation to dry the sheathing made cold by the extra thick insulation, cold sheathing carries more moisture (correct?). A rainscreen is one of the recommendations to help dry the sheathing.
But what if there was an airgap between the insulated interior side of the sheathing and the exterior wall cladding side of the sheathing. From inside to outside a super insulated double stud wall assembly could go like this. 2×4 interior stud wall with a gap of chosen size to accommodate desired R value. 2×4 load bearing wall. A WRB applied directly to unsheathed 2×4 frame. A second layer of 2×4’s nailed like furring strips to the 2×4 frame creating a 3.5″ structural member to the nail the sheathing to. A rain screen can then be applied to the sheathing.
Would this be able to accommodate a super thick insulation cavity in the double stud wall without concern for moisture on the sheathing? Would this pass as still applying the sheathing directly to the bearing wall? Does this negate the need for an interior air barrier as there is no longer concern for outward vapor drive? All comments welcome I’ve just started to mess with sketchup so I apologize for the very rudimentary wall assembly model.
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