[cantonstf]

I'm doing a tub/shower surround and noticed that one end of the cement board is sitting on the tub ledge. The rest of the cement board is 1/4" above the ledge. I think this will be a problem down the road, but I've already ripped the whole thing out once and I'd hate to do it again. Any suggestions?

Used 6 mil poly as vapor barrier. Still have one wall to go with cement board.

[oh'mike]

Is the board above the flange or is it overlapping it and causing a bulge?

[cantonstf]

The board is in front of the flange. We furred out the back wall to have the cement board drop in front of the flange and end up 1/4" from the tub ledge. The picture may look like a bulge, but it's flat there.

[oh'mike]

You should be fine---what is your question?

[md2lgyk]

If you're worried about it, use an angle grinder with a masonry blade and trim a bit of the board off.

[AllanJ]

There are two reasons to not have the wallboard touch the tub lip:
1. To prevent stress and cracking due to expansion during temperature changes,
2. To reduce wicking of water up into the wallboard. This is probably not a problem with cement board as opposed to drywall but a gap of less than 3/16 inch will not prevent wicking. Wicking problems are further reduced by proper maintenance of the caulking around the tub edge. Concrete is porous. The danger of continuous wicking is mold impregnating the cement.

[woodworkbykirk]

exactly allan you said it before i did

[cantonstf]

Thank you, gents. I think I'm being too particular and I went ahead and took everything out and will be doing it again. I guess when you've done a lot of surgeries you know what's important and what's not.
Still learning.
Debbie