Am I asking for trouble?
I may need to switch to a 2×6 load bearing exterior wall as my outer wall cannot be load bearing but had to be changed to a “Larsen” like truss. To maintain about the same total wall depth I’m considering an inner 2×6 load bearing wall sheathed on the exterior with OSB and filled with mineral wool r23 and a modified Larsen truss 2×6 wall outside. I’m envisioning the trusses as frames of 1×2 with pieces of Thermoply on one side at both ends and filled with mineral wool (about r19). Should I stagger the studs? or put them inline? Staggering the studs gives a bit higher effective r value but at a bit more condensation risk to the OSB at the cold sripes where the outer “larsen” stud is. With half the r value on each side of the OSB (between aligned studs) I’ll need to keep the interior dew point below 30 f to be safe at -10f outside, which the ERV should be able to do. Is half the R on each side of OSB too risky?
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