Matching Rock Lath + Float Wall Thickness With Cementboard

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Probably an easy question, but I'm looking at tearing out my existing standard 5' wide shower that is rock lath + float + tile ... super thick oldschool stuff. I'd like to try an leave as much wall intact in the rest of the bathroom, so that means trying to blend the old and the new.

I expect when the shower walls are cut out there will be a distance of 1"+ from the rest of the intact walls to the studs. Do people generally stack cementboard to get a similar thickness, put spacer strips behind the cementboard, only rip out entire walls?

It's a fully tile shower, all walls + ceiling. I'm hoping I can chip off the ceiling tiles and smooth the surface then paint instead of having to bring the ceiling down also. Fools errand?

If it helps I likely will be going with a fiberglass pan, and tile walls, I know the pan generally attaches to the studs and likely has a limit to the wall thickness that might complicate things.



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I think you'll have a problem getting the tile off of the ceiling, but you might get lucky.

A typical shower receptor won't have a tiling flange that deep, so you'd probably need to put some blocking against the existing wall structure to compensate. If I were going to do this, I'd probably put some cleats on the existing studs to bring the surface out where you want it. That will also allow you to ensure you get the attachment points all in a nice flat plane, and ideally, plumb (but the existing wall may NOT be plumb - the shower I put in my mother's house had the plaster walls over 3/4" out of plumb from the top to the bottom).

Tearing out lath and mudded walls is a messy job, and the lath can make some nasty cuts, so be careful. Getting a clean cut between the area you want to save and the new shower will be key. is my goto place for tiling is great for the plumbing aspect, but there are lots of tiling pros over there.
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