# Installing Kerdi board in bathroom



## JP's Dad (Aug 7, 2012)

I am going to install Kerdi board around my bathtub and tile the walls from the tub to the ceiling on 3 sides (it will be used more as a shower than a tub!). I’ve been researching Kerdi board and have decided that it will be the best substrate for the job. However, I have some questions on installing it that I haven’t found answers to and am looking for someone who has installed it in the past to help me:
1. I have heard that the tub should but against the Kerdi board, not have the kerdi overlap the edge. If so, how do you seal it?
2.	How do you determine what thickness of kerdi to install? The wall where it will be mounted is terra cotta bricks (picture attached). I’ve been told that I can thinset the kerdi directly to the bricks and then tile over it. The wall is uneven due to 90 years of settling. 1 inch? More? Less?
3.	When you cut the kerdi and butt it against another piece at a 90 degree angle, you will get an exposure of the foam. Does that have to be sealed? With what? 
Thanks for any insight on installing this!


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## joecaption (Nov 30, 2011)

#1 I would get rid of that window!!!
A window in a wet area is going to be nothing but trouble!!!
What's the first thing you do if there's a window there? Cover it up with a curtain, So why is it there?

#2 I would build that wall out so I could get some insulation in there.


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## JP's Dad (Aug 7, 2012)

The wall is interesting: It is made out of terra cotta blocks (about the same size and shape as cinder blocks). They actually insulate very well with their airpockets (house is nearly 90 years old). The few tile that got damaged during the demo will be filled with insulation, but the rest are fine. The exterior is brick. The total wall is 14 inches thick. Removing the window is not an option due to it's placement on the house (it would destroy the look). So, need to work with what I have unfortunately


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## Blondesense (Sep 23, 2008)

I considered using it when I did my shower. Their website may have answers to your questions. 

http://www.schluter.com


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