Correcting uneven CBU in new shower enclosure - possible?

[meiks11]

Hi all,

We're currently working on finishing our walk-out basement and are installing a shower with a tiled surround as part of that project. The problem is that we had our drywaller install the CBU, and it's not level. At all. I'd almost say it's wavy, in fact. The CBU is mounted directly to studs (with an isolation membrane, of course) spaced 16" apart. The studs should be pretty straight and level - the house is only six years old, the drywall came out fine, and I think we did some quick checks of that earlier on in the project.

The question: Is there any fix to this that doesn't involve tearing off the CBU and redoing it ourselves? My initial thought was to lay on the thinset, but I'm concerned that the waviness is too significant for that to work well - we're talking closer to 1/4" than 1/16", varying across the wall. And if we do need to tear it out, how do we prevent this from happening again?

Thanks in advance for your help.

__________________________
meiks11

[Davestone]

You may well have the plumbing that is messing it up, when they nail those metal guards on there it holds out the cbu, i always have to do some flashing with thinset i wouldn't tear it off, i would skim it with unmodified thinset and even it out,unless it's too bad, and the thinset runs, then i'd use mud.

[meiks11]

Thanks, Davestone, I think you saved us a lot of work. We probably would've ended up tearing it down and ended up with the same problem we have now. How bad does it need to be to require mud? Or is it just trial and error?

Thanks again!

meiks11

[bbcamp]

Thinset should be only 1/4" thick ,or less. By mud, Dave is referring to mason's (brick) mortar, in this case.