Cement board butting up against drywall (installing, bathroom, shower, leak)

[DIY in SCP]

Installing a tile shower. I had to shim out the studs that the cement board is attached to

So now I have 1/2 inch cement board that is shimmed out to about 5/8 inch. That will butt up against already installed 1/2 drywall as it exits the shower stall
This is a renovation in an existing bathroom.... and I surely don’t want to replace all the drywal.
I had considered using 1/4 inch cement board, and shimming it out flush, but don’t feel
Comfortable using 1/4 inch for the tile backer

Any sugggestions for how to merge these together?

[LIcenter]

Huh!? Why on earth would you shim it out, knowing the drywall is the same thickness as the cement board? Pull it down, and remove the shims.

[DIY in SCP]

If that was an option, absolutely - that would be a simple fix.
FWIW - the cement board isn’t even hung yet...... but I am going to have to shim it.

Long story, but the shims were a necessity. Looking for any input on best/easiest ways to deal with the depth discrepancy


If it makes it easier to visualize, imagine 1/2 cement board merging into 3/8 inch drywall.

[kevink1955]

You sometimes shim tile backer to allow the shower pan liner or a precast pan to run behind it to ensure proper drainage. you would not want the pan in front of the backer and tile it's a definite leak point. as far as the mismatch, take down a little more sheetrock and shim 1 end of the new sheetrock to match the backer

[DIY in SCP]

Ah Kevin...... thanks.


Such a simple solution - once someone points it out :-)

That would work Plenty of flexibility in the drywall


Thanks

[K'ledgeBldr]

Originally Posted by kevink1955

You sometimes shim tile backer to allow the shower pan liner or a precast pan to run behind it to ensure proper drainage...

Nope, no need. You don't want the backer board overlapping the flange- the closer it gets to the actual surface of the tub or shower pan the more likely it is to absorb moisture.

I prefer and spec 1/2" Durock- it is installed just shy (1/8" or less) of the flange; the tile will be set from the tub surface whatever size the groutline is. So again, the backer board would be flush with the surrounding drywall surfaces (no flaring due to overlapping the flange). In the OP's circumstances it would appear that he has house with 3/8" drywall. This of course would negate the use of 1/2" backer board because it wouldn't be flush with the surrounding wall(s). Or, as I stated in my previous post, a cap tile would have to be used.