Tub shower bathroom [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


View Full Version : Tub shower bathroom

07-03-2019, 12:51 PM
Working on my last bathroom and it is a tub shower.. plan durock cement board and then durock membrane for my waterproofing if the walls...tub and rough plumbing r in (plumber did today)but I noticed an issue with the flange of the tub...2 of the sides are about 1/2 inch and the other is 1/4 inch...instructions are to add furring strips 1/4 inch so the backer board is flush with the flange...this seems like it is gonna messs up my finished tiled wall to drywall transition...advice besides getting new tub? Add 1/2 inch furring to 2 sides and 1/4 to the other? 1/2 inch furring all around?

How long nail should I use to nail in 1/2 inch furring strip—want to make sure it is strong enough to hold the board and tile

Some pictures to help

Was planning for some 1/4 tile to transition from tile to drywall...


Sponsored Links

07-04-2019, 05:53 AM
Why can’t I just add 1/4 furring to the two 1/2 inch sides then put the cbu on this the front side of the cbu will be 1/4 inch in front of the flange...on the 1/4 inch side just put the cbu up..extend the durock membrane an inch or so not attached to the cbu at the bottom...

07-04-2019, 07:54 AM
Not sure I'm seeing the problem, Keven. You're stopping the CBU above the tub's tiling flange, are you not?

07-04-2019, 08:35 AM
Kohler says to have the cbu in front of the flange..ie the back side of the cbu is touching the front of the flange...the top lip of the flange is not the same on all sides...1/4 on one and 1/2 on the other 2...I thought u needed the cbu to cover the flange...not just meet up with the lip of the flange...

07-04-2019, 08:52 AM
Or cbu to come down to tub deck...looks like people do it both ways...I would rather not put furring strips to exend the wall out...of the cbu is flush (or slightly beyond) with the vertical portion of the tile flangeu could u not just extend the membrane down to the tub deck?

07-04-2019, 09:20 AM
What I’m planning to do...cbu flush with the vertical portion of flange...have about 1/16 to 1/8 inch space between the top of flange and cbu...membrane would go down to tub deck

07-04-2019, 09:36 AM
Keven, the more correct method to my thinking is to have the wallboard fall inside the tiling flange, but with the sheet membrane you'll be using I have no problem with stopping the wallboard above the tiling flange and bonding your membrane to the tiling flange and the wallboard. You can use that method all the way around your tub, even where the flange is thinner.

I think it's a good idea to give the membrane a bit of a wedgie at the wall/flange gap to allow for movement. Kinda like thissy here, but substitute Durock Shower System membrane for the Kerdi inna drawing (provided by our own Tonto Goldstein):


My opinion; worth price charged.

07-04-2019, 12:13 PM
Walls r flush with the vertical surface of the flange...except on the back wall as the cbu juts our 1/4 inch...since that was the thin side of the tub...
1)any need to caulk the gap between the cbu and top of flange or since membrane will be present no need?
2)what else besides durock seal or Kerdi seal could I use to fix the membrane to the vertical flange?
3) if I fix the membrane to the wholeflange (vertical region)how can I give it a wedgie ? Do I only partially fix it at the bottom 1/3 and leave the rest not attached and a slight wedgie in that region? Tub is set on cement floor so should move much (acrylic tub also)keven

07-04-2019, 12:39 PM
1. no need

2. Just Kerdi Fix or equivalent

3.That will work

I usually set tub on some gobs of mortar (not thinset) regardless of mfg. saying it's not necessary. Keeps bottom from deflecting, accommodates uneven floor and stabilizes tub to some extent.

07-04-2019, 12:55 PM
Yeah Pete that is what I expected the plumber to do but that didn’t heppen