Just bought my first house and doing a lot of the work myself. I want to add electrical and audio lines but I want to make sure the walls are straight first. I've seen some videos where the guy cracks new wall studs to move them back, but I don't have the luxury as the vanity side wall is adjoining a finished room.

I've laid a straight edge along and identified a few studs protruding into the room more than the rest and I'm unsure how to

1.) make sure the plane of all the studs is even. 2.) While doing so, getting the corners closer to 90 angles.

The house was built in the early 1900s with 2X6 walls and 8'6" ceilings.


3 Answers 3


The easiest route to getting a straight, vertical wall is to identify the furthest out studs and then shim out those studs that are not as far out. Similarly, find the area on each stud that is furthest into the room and then shim the recessed areas of the stud to match.

Shimming can be done using cedar shims, sold by the bundle in big box stores and lumber yards. They can be broken to get the right size and length and tacked in place with a stapler or brads.

Not every inch of the studs has to be shimmed. I would try not to leave a gap of more than about 12 to 18 inches though.

If there is only one stud proud of the rest, I might try to shave that down, but if there are several, proud or leaning, I would use shims.

Getting to 90 degrees is a bit tougher, and is usually only done if there are cabinets that simply must be flush with the side wall. More often the edge of a cabinet near an untrue corner stops an inch or two short of the adjacent wall and is completed with a trim strip.

If you need to get a perfect 90, you can use a framing square in the corner to see where the error is, and which wall needs to be adjusted to accommodate. If the difference is enough, you might even need to rip a thin shimming strip for each stud to adjust, or even sister a stud next to, but proud of, the existing studs as a nailing piece to hold the drywall (sistering is attaching a parallel board of similar size next to an existing board for strength or better positioning).


If the original studs were mostly plumb and not too bumpy, I planed off the high spots and shimmed the low ones. If they were not plumb or quite bumpy, I just sistered new studs to them. Sistering was almost always required to square the walls. I had to do that in both the kitchen and bath.

As an engineer, the easiest way to verify square to me is pythagorean theorem. The quickest shortcut for that is using a 3-4-5 triangle. Measure along the toe plates 3' on one wall and 4' on the other. Distance between those marks along the diagonal will be 5' if it's square. You can do the same with the top plates though you know if the bottom is square and the studs are plumb that the top would also be square.

  • Is measuring 3/4/5 easier for you than using a carpenter's or sheetrock square?
    – wallyk
    Commented Oct 4, 2016 at 18:47
  • 1
    @wallyk Most sheetrock squares I've seen are really Ts. Carpenter squares are good for a quick check of the immediate corner but not good enough for an entire wall. I often do a 6-8-10 or a 45 degree triangle to get the biggest triangle that will fit the walls. Same thing when I'm laying out new walls.
    – topshot
    Commented Oct 4, 2016 at 19:01
  • The beauty of the the 3/4/5 method is that it can be multiplied for extra accuracy, 6/8/10 feet for example will give superb accuracy. Holding a 2 foot square in the corner is a notoriously inaccurate way of judging the true 'squareness' of two adjoining walls.
    – handyman
    Commented Oct 11, 2016 at 18:57

You mentioned the fact that there are cabinets in adjoining rooms, old plaster, and other complications. Those factors may make this technique inappropriate, but it's worth mentioning.

If you have a stud that's bowed in one direction, cut 2/3 through it from the accessible side. This creates a hinge point but doesn't risk serious settling or other movement if done one or two studs at a time. Then...

If you've cut the convex (protruding) side of the stud:

Push or lever the stud slightly past straight and screw a 3-4' or longer scab stud to the side of it. Expect some relaxation movement when you release pressure. You can also attach one half of the scab and use the other to lever the stud further into place. Start with the lever half sticking out past the stud a quarter inch or so, then push it in flush to remove the bow, and screw it in place.

If you've cut the concave (inset) side of the stud:

Push or lever the stud 50% past straight and drive a wood shim into the now-widened cut. Expect some relaxation movement here as well. It's not unheard of to do this more than once on a severely bowed stud--say at 1/3 and 2/3 of its length. Once that's done, optionally apply a scab stud of an appropriate length to stabilize.

You can use this technique on one or several studs in a wall even without the scab studs. The remaining studs, drywall, and any cabinetry all serve to adequately stiffen the wall as a system.

  • A diagram would go a long ways here. When you say "bowed", do you mean sideways (like within a wall) or do you mean bent to stick out of the line of the wall?
    – wallyk
    Commented Oct 4, 2016 at 19:49
  • You won't be able to straighten a stud that's bowed sideways in the OP's case since it'll be fastened to the plaster on the one side. Also, studs bowed like that normally don't present a real problem for the final product.
    – isherwood
    Commented Oct 4, 2016 at 20:21

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