Expert: Bruce E. Johnson - 3/31/2009

Question
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: Hi Jeff, I have never used one in all the tile work I have done. I generally just make sure I grout everything real well and seal the grout.  I can see where it might be a good idea if you get a lot of water splashing around everywhere and don't clean it up.  My latest tub surround I did with a maple top and a tile backsplash and haven't had any water leakage problems or anything.  If this is a concern you can get self sticking flashing (peel and stick) that is used around exterior windows.  It is a rubber product and can be anywhere from 8-16" wide and comes in a roll 25-100 feet long.  It is easy to install and probably a lot cheaper than the tub tile flange you are talking about. You just peel the backing off and stick it down.  After it is installed you can thinset your tile right to it just like you would a vinyl shower pan.   I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com





---------- FOLLOW-UP ----------

QUESTION: Bruce,

I got the following answer from another expert on the AllExperts website.  Can you comment regarding this answer?

Answer from other expert:
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

Answer
Hi again Jeff, true, grout is not waterproof unless it has been sealed properly.  However it also is not a sieve that allows water to blow into the wall cavity unabated.  Water in a shower flows down and then out.  Water in a tub flows out the drain, minimal water even gets on the tile during a bath.  So I guess it is much ado about nothing.  If you want a completely waterproof system go with a fiberglass one piece enclosure and then tile over that.  Like I said in my previous email, if you have an area that requires additional waterproofing then you have several options available.  I mentioned one of them.. I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com