I’ve got alittle history of hanging drywall as a do it yourselfer but I’ve never seen butt joints placed between joints or studs purposefully. I mentioned it to a building inspector here in Mobile, Al and he had never seen it or heard of it. So, is it legal, per code. Is it something legal by default?, is it in the code? I can see how it could save drywall, and how it could help with creating a valley for butt joint finishing. But again how are you allowed to do it?
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If for some reason, the drywall is considered a part of a shear wall assembly (and it's hard to figure how), then they probably need to have joints fall on a stud or joist or solid blocking.
Perhaps in a party wall situation?
The question arises, what's the difference-the bevels don't end on solid blocking (even on a garage / house fire separation wall), so why would there be a requirement for the butts to be attached to a stud or joist?
Having never hung board out of the norm, I cannot say.
What did your impector say in regards to code compliance?
I have seen butts between studs - a plywood backer is used with a drywall shim on the outter edges of the ply backer so when the joint area is screwed to the ply it actually bows the joint inward. It's my understanding it's most commonly used where an extra flat/smooth finish is the desired end result.
On remodels I've used ply backers when adding new drywall to old if it would be hard to cut back the drywall and add a nailer to the stud - especially around inside corners of existing walls where it's less time consuming to add ply backing rather than have to tape and texture the corner and involve part of the wall perpendicular to the one I'm working on. I'd rather have a ply-backed joint a foot from the corner so when things are feathered out I'm not having to repaint the other wall.
A joint made inbetween studs in this fashion is actually much more solid feeling than a clear span, and I've never had cracks pop up down the road so it's a good concept for some situations.
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I continued to follow this issue and came accross a reference that clarified it. There is a difference between the IRC and IBC. The IBC 2009 references a ASTM table which notes that a joint parallel to the supporting structure must be supported hence these products and adaptations for "bending" dywall at butt ends. The IRC strictly says end drywall on supports - studs, joints, etc. So know what code you are operating under and how your inspector feels about it.
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Can you cite the passage here on the IRC rule you found?
because " The IRC strictly says end drywall ", which could be interpreted as meaning that drywall cannot fly at it's end. A joint in the field might not be considered "end" other than the end of a sheet and the beginning of another which you would be supporting by a block or strip of wood to join the two together.
As I understand it, a full width plywood backer is recognized as a propper support - there is a specific refference for it in a drywall related standard of some kind, but I've never seen it, and have never had to - at least with the IRC inspectors I've worked with.