Expert: Dan Griffin - 3/31/2009

Question
I am completely upgrading our bathroom.  I am going to be installing a new bathtub soon.  The bathtub is a drop-in tub.  The manufacturer sells a tile flange.  I was told this is basically a strip of rubber-like material that goes 6 inches up the wall to prevent water from getting up behind the tile.  Before this I have never heard of or used a tile flange when tiling a tub or shower.  

I am planning on using wonderboard on the walls around the bathtub.  The tile will then go over the wonderboard.  My question is:  with the tile, grout and wonderboard do I really need a tile flange?  My feeling is that this tile flange is just a marketing ploy to get people to spend their money unnecessarily.  

Answer
Jeff, tile and grout are not waterproof.  Wonderboard is not waterproof. I am not familiar with a "tile flange".  Be aware that some tubs are coming out now that do not have a raised flange, apparently the caulk is expected to be a total seal.

It is a typical recommendation to install a membrane behind the Wonderboard.  A more recent solution is a Schluter material called Kerdi which is installed on top of the substrate.  There are several other sytems similar to Kerdi - Mapei makes one. You might go here for more information:
http://www.johnbridge.com/

the actual article on Kerdi is here:
http://www.johnbridge.com/kerdi_shower.htm



Jeff, I re-read your question.  I think they are offering a piece that screws ar glues to the tub for the tile to terminate on.  This would be a bit similar to the old tubs that had a rim or flange that attached to the studs and turned the water into the tub.  No idea on the cost, I've not used one, but I would stringly consider it depending on details.