Hello, I just installed an acrylic tub and now have to put the cement board up. My problem is that the back and right walls are fine but on the left side the wall is not square. The front corner touches the studs, but there is a gap that gradually gets up to almost 3/8" in the back corner.
One solution I've thought of is cutting strips to shim behind the cement board, but that sounds difficult to do. Is it possible to use shims at the bottom of the cement board where it meets with the tub so that it ends up close to flush with the flange? I'm worried that this might cause the cement board to crack. Please tell me I'm wrong.
Any thoughts would be much appreciated.
Thanks!
Elijah
Thunder bay, ontario, canada:cool:

Eli, you are planning to have the backerboard overlap the top lip of the tub, right? You can shim to achieve your needed correction but I would make that shim a sliver about 3' long so it will be very gradual. I usually rip a 2x4 on a very slight angle to make my tub and shower shims. The cementboard is fine but I much prefer Hardibacker James Hardie Backerboard

Eli as usaul ballenger got it dead on when I run into this problem I shim about 5 feet but 3 will work fine and believe me the extra work pays off in the finished product. GOOD LUCK, AC