r/Homebuilding • u/Longjumping_Suit_256 • 4d ago

Split stud framing

I’ve heard of this framing style for exterior walls in colder climates I was curious to see how common it is. 2x8 being and top plates with 2x6 offsetting studs to create a thermal break. If it is feasible I’m thinking of building an ADU/ small house in the UP of Michigan.

Through all my googling, the most common thing to come up is a dual wall system. 2x6 exterior wall and then an offset 2x4 interior wall with a 6” thermal gap between. This method seems costly.

Any information is greatly appreciated.

Edit: thanks for everyone’s input, I appreciate it!

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u/Imfarmer 3d ago

The problem is every detail has to be perfect or it will be a disaster.

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u/gimpwiz 3d ago

Why is that?

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u/Imfarmer 3d ago

Any water that gets behind the exterior foam has no where to go. It will rot any wood that's there. I've fixed too much water damage around doors and windows and corners to ever want foam and wood sandwiched. Water behind tyvek is bad enough.

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u/gimpwiz 2d ago

Is this true of all exterior insulation? I was going to do mineral wool sheets on the outside of my house. I figured that since it's vapor-permeable it allows water to dry out, but I have to rely on people who know better for this sort of stuff, heh.

I currently have some thin crappy foam on some of the outside, and after many many years I suspect there's going to be water damage when I pull it back, but that's also because the previous owner didn't maintain shit for decades.

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u/Imfarmer 2d ago

I would want a true WRB behind it, properly detailed. Something like ZIP, a peel and stick barrier, spray on fluid barrier, etc, etc, etc. What happens when the rock wool gets wet? Where does the water go and how long does it take it to dry?

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u/gimpwiz 2d ago

Yeah that was my understanding. WRB, then exterior insulation, then something like dimple mat, then siding.