Double stud wall with interior (non-loadbearing) thin wall?
I am building a new home at 8500ft in Colorado. The house has been framed and the roof is on. The 2nd/interior stud wall has not been built yet (on purpose). The wall will be dense-packed with cellulose.
I want more space between the exterior 2×6 load-bearing wall and the interior non-load-bearing 2×4 wall.
Is there any major complication if I turn the 2×4’s flat to the wall (thin wall). My inspector tells me there is no code requirement so I can do it, but my walls might not be as flat. I think that can be solved by sorting for straight studs and using 5/8″ drywall.
I want to run it by the experts here to see if there are other pitfalls.
Pros:
I can run all the plumbing and electrical on the 2×6 studs without drilling holes.
I won’t have to use nail plates to protect the plumbing and electrical.
The thermal gap between the double studs will be wider, which might slightly improve performance.
Cons:
The interior wall will be a bit more labor-intensive.
I will need to tie the interior wall to the exterior wall with some plywood strips in a few places to ensure the interior wall doesn’t bow in the middle when the cellulose is dense packed.
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Replies
mhenson,
Code allows it, but you don't see it used because it yields such a poor wall. The physics is against you. Straight studs and 5/8" drywall won't do much to mitigate that. The deflection is eight times what it would be with the studs installed as they usually are. That will show up in the dense packing, when you install cabinets or shelves, and just pushing against the wall.
Orient the studs the regular way, the benefits outweigh the costs.
Run the 2x4's and 2x6's offset from each other and you can snake wiring between them.
You shouldn't be running plumbing in exterior walls anyway.
The snaking makes sense and it seemed like a flimsy assembly. I have plumbing in three places that require running the plumbing in the exterior wall. There will be 2 inches of ISO on the exterior behind the rain screen and the pex will be run between the stud walls. It is an unavoidable and low risk that it might ever hard freeze in 5a.
Thank you for the advice I knew there had to be a reason you never see them.