Fixing out of plumb wall

[PAB]

Hopefully a simple and easy question .

My studs are out of plumb by about 5/8″ over 8 feet. I will be putting kerdi board on it and it is my plumbing wall. the wall is flat horizontally. it is not load bearing.

Tapering shims to make this work would be very difficult for me (if not impossible). some of the studs have plumbing attached (or blocking) so sistering an entire 2×4 is not possible.

I used drywall shims to make one of my walls plumb and flat, and used wet shimming for another wall. however, this has me stumped.

Could i add shims (maybe about 6″ in length), doubling/tripling up where needed (to ensure plumb), to only the areas where the kerdi screws will go? The kerdi board would be properly supported where screwed in, but there would be empty space between the board and the studs in certain areas. or perhaps do something like I did here with pieces of 2×4 in the attached pic on the leftside stud to provide backing for screws at intervals?

kerdi board needs screws every 12″ along the studs.

thanks.

 

[WorthFlorida]

I think you answered your own question for the most part. The areas where the board would not be flush up against the stud you can put down a heavy bead of construction adhesive to fill the gap. Don't push the board against it too much otherwise when the board springs back it can pull the adhesive leaving gaps. Construction adhesive dries hard so it should provide support. To get the wall vertical plumb, I've used paint sticks to shim up or tapered shims. Where there might be gaps you do not have to full seat the screw against the stud. Use a wood countersink bit to make the dimple in the board then put in the screw until the head of the screw is below the surface.

 

[Sponsor]

 

[wwhitney]

Does the whole wall between corners need shimming, e.g. on a shower? If the wet area of the wall is contiguous with a dry area, you're going to need to figure out how to handle the transition from the tiled area you made plumb to the adjoining drywall that isn't plumb, or else shim the whole wall, which can be hard if there's a door opening or window in the wall.

5/8" over 8' is somewhat over 1/16" per foot (that would be 1/2" over 8'). You might just try stair step shimming each stud, rather than taper shimming them. That is, prepare some shim stock 1-1/2" wide in varying thicknesses, multiples of 1/8" up to 5/8", from rips of plywood or solid sawn material. Then mark each stud at the heights where the ideal shim thickness is exactly 1/8", 1/4", etc. In the 1/8" to 1/4" section, use an 1/8" shim; in the 1/4" to 3/8" section, a 1/4" shim, etc. Then staple a 1/16" drywall shim to the lower half of each separate shim. Finally use a bit of construction adhesive on the lower half of each step to fill the remaining tapered void at the time you install the kerdiboard.

Cheers, Wayne

 

[PAB]

thanks so much to both of you for your replies!
wayne, do you think i could use the drywall shims and stack them up instead of using the wood shims? i found getting thin strips of wood cut safely on my table saw a little daunting. i have found the area where i'd have to place two shims, then three, etc.
if so, can i still use construction adhesive on the cardboard shims? or maybe the thinset that schluter recommends to wet shim. this would mostly as you say make up for the areas where there is space between the shims and the board.
these are the ones i have. i bought plenty.
https://www.menards.com/main/buildi...7-c-13059.htm?tid=-2015673927182954033&ipos=1

 

[Jadnashua]

I'd not use construction adhesive on Kerdiboard. I would call their tech support line and ask them for their suggestions. Wooden door shims when you place two at 180-degrees, can be slid to produce varying thicknesses, cut them in length to get the thickness you want.

FWIW, the washers you use with Kerdiboard are dome-shaped to cause the washer to dimple the panel and recess the screw-head...no special action required.

 

[wwhitney]

wayne, do you think i could use the drywall shims and stack them up instead of using the wood shims?

Those are 1/16" thick, I'm leery of stacking up 9 layers. You could get some 1/4" plywood and some 1/2" plywood, and use a combination of the 3 materials. (I've been assuming you need to build up the bottom more than the top, otherwise reverse top and bottom in my description).

First you'd figure out the height at which the 1/2" plywood (may be 15/32", check) is the correct thickness and then use a long strip from there downward. Then figure out where the 1/4" plywood (may be 3/16" or 7/32") is the correct thickness, and use a strip from there down to the 1/2" plywood. Then add layers of drywall shim as required.

[Optionally use 3/8" plywood instead of 1/2", and/or add some 1/8" plywood to reduce the number of drywall shim layers.]

Cheers, Wayne

 

[John Gayewski]

I think i would snap a line onto a 2x4 and cut a shim by hand with a circular saw. Error on the side of being too thin. That would let you use a shim in a belly of you had one that needed it. Glue your shimms to the studs. This is actually easier that it sounds.

One time I cut an entire 2x4 studded wall, in place, with a multi tool, top to bottom... Every stud over the length of a shower (5'). I had no choice. That was some cussing.

 

[PAB]

Thanks again everyone for your advice!

Jim - I think I'll take your advice and ask schluter about the construction adhesive. also i'm curious to hear what they have to say about wet shimming (using thinset which they recommend) on top of the cardboard shims. something tells me it shouldn't be done but i'll check. they have an online course this afternoon so i'll try to ask then. btw i do have those washers and screws which is what i've been using.

John - I think that would probably work but i honestly think it's beyond my capability to cut it that accurately. thanks though for the feedback.

Wayne - i now have some long shims that are 3/16, 1/4, 5/16, and 3/8. once i setup my table saw for safely cutting these strips, it wasn't too bad. i think i'll try what you're suggesting. but i'll wait on schluter's suggestions regarding adhesive and the cardboard shims. at the very least i could put the cardboard shims underneath the wood shims that i cut, and then wet shim using thinset. however, wet shimming with thinset isn't as easy (for me) as the videos on youtube make it seem, especially considering i've only worked with thinset once so far (and that was the time!).

Thanks again everyone for your help. I'll try to report back once I hear from schluter.

Paul

 

[PAB]

I also have to worry about my delta multi-valve as I set it up accurately (distance to the finished wall) prior to needing to shim. i think i'll still be within tolerances but it will be interesting.

 

[wwhitney]

Wayne - i now have some long shims that are 3/16, 1/4, 5/16, and 3/8.

If you have enough of those, then you only need to use cardboard (1/16") shims for the 1/16" and 1/8" regions. E.g. 7/16 = 3/16 + 1/4, etc.

Cheers, Wayne

 

[Jadnashua]

With the tapered door/window shims, you can go from barely nothing, to twice the thickness of the taller end as you slide them along each other while keeping the outer edge parallel with the stud.

 

[PAB]

I asked schluter during the training session. they indicated it must be thinset. also the person from schluter indicated he doesn't see any problem with thinset on top of the cardboard shims. so far with the step shimming it appears to be going well. i haven't even used any of the drywall shims - just the wood - and may simply at this point use the wood and then thinset to smooth over the "steps" as well as the small (1/8" and less) areas.

thanks!