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Community and Q&A

Insulating conventional corner

kevek101 | Posted in GBA Pro Help on

I’m converting our 2car attached garage into conditioned shop. I’ve began weather sealing and am trying to decide what to do with the conventional corners box corners. Not sure what the proper term is for that but I’m referring to how the last and first stud in a corner of two perpendicular walls meet so that they essentially form a post, or a situation where there is an empty cavity facing the exterior and now way to access it from the interior.

I’m thinking I should:
-cut out one stud out and toenail it back to the sheathing so it’s oriented like a “California corner”?
-just wrap the stud corner as it is in rigid foam to at least stop the thermal break. Im furring out the walls from 2×4 to 2×6 so there’s room.
-not sweat it because this is just a garage and though it will be insulated and heated, it may only be kept at 40-50 degrees, and there should be little humidity. Besides the big leaky garage doors are the baseline for efficiency.

Other details:
2×4 walls with double top plate, shingle siding and i will be insulating walls with rock wool.

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  1. GBA Editor
    Martin Holladay | | #1

    How you proceed depends on how fussy you want to be, your available time, and your budget.

    If you want to, you can drill holes in one stud and fill the void with spray foam -- either from a whole lot of small aerosol cans, or from a two-component foam kit.

    You can drill one or two holes and fill the void with blown-in cellulose -- ideally, dense-packed cellulose.

    You can use a Sawzall to remove half of one stud -- ripping it from 3.5 inches to 1.75 inches wide -- so you can access the void and stuff it with fiberglass or mineral wool.

    Removing a stud and rotating it is possible, but you have to think of all those sheathing nails.

  2. GBA Editor
    Patrick Mccombe | | #2

    The short walls on both sides of a garage door can be very important structurally as they resist overturning forces experienced in high winds and earthquakes. I don't think I'd bother messing with them, as the small improvement in efficiency for a shop doesn't seem worth it, especially since, as you point out, the garage doors are the real problem.

  3. Expert Member

    As patrick pointed out. The walls resist serous enough forces that Simpson makes shear-walls just for that situation.

  4. kevek101 | | #4

    Thanks fellas. I was concerned about changing the framing. Definitely not going to do it now. Probably just pass on trying to pump insulation in there too, all things considered. Maybe just try and seal things up as good as I can and move on.

  5. Jon_R | | #5

    Independent of this issue, strips of polyiso foam on the studs are a good idea.

  6. Expert Member

    Projects that plan on adding foam strips on the studs need to be framed differently, particularly at corners and partitions.

  7. CMObuilds | | #7

    Where do you live? If you are not in some sort of high seismic area...

    Cut it and rotate it, that stud wasnt installed for shear value, that stud was installed because that is the foolish way people (still) frame because that is how they thought you gave a nailer for the corner. It can also depend on how wide the panel is that the stud is a part of.

    After you cut the top and bottom free a flat bar will pull the stud off the sheathing. In my area it is a waste of a stud, like when people frame a wall stud on either side of a partition wall.

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