Asked on Jun 08, 2018

What is the best way to prep under a tiled shower floor (2nd story)?

by Joh22287908
I have a wood frame house and need to update bathrooms (plumbing and tub and fixtures are all old and in need of repair). My husband wants us to expand the shower space to a nonstandard size. The questions I have are what to use under the tile to slope the floor to the drain, what kind of mud to use on cement board for the seams, and how to make it completely water proof underneath if the tile ever cracks (small circular bits of marble tile in random sizes). Schluter Ditra accomodates for movement, but not waterproofing per se & jacks up the floor height...I see a lot of options that claim to be the best solution- any experience on these products? I also need to frame in a bench seat. Should I be covering it with anything before tiling? Thanks!

  4 answers
  • Cindy Hagemann Cindy Hagemann on Jun 08, 2018

    Build your shower and bench and use cement board, mud it, lay plastic sheeting and then tile.

  • Zac Builds Zac Builds on Jun 08, 2018

    Ok so you'll want to start with a shower pan liner. This is a thick rubberized membrane that you can buy from the home improvement store. You'll attach it directly to the wood frame of your home. With a single uninterupted piece you'll want to create a pan that comes up the wall atleast 12" the whole way around the base of your shower. In your case since you want to add a bench you'll also have to do the same thing around the bench. Any horizontal surface needs to be lined.

    Next you will install your concrete board. On the wall you'll to come down over top of your shower pan liner. Right to the floor.

    To fill the gap between the concrete board you can use a high quality tile mortar.

    To slope the floor to the drain use a sandmix cement and add an acrylic binder to it. Mix it until its about the consistency of raw cookie dough and then transfer it to the floor of your shower. You'll have to work it with a trowel to slope it to the drain. You'll want at least a 1/4" of slope for every 1' of run. So if your shower is 4' wide your floor should be 1/2" taller around the perimeter than it is in the center (where the drain is).

    Then apply your tile.

    Let me know if you have any other questions!

    • Joh22287908 Joh22287908 on Jun 08, 2018

      Awesome! Thanks! Since you were able to answer all of it, two more questions... Since the bench will require cutting a liner to fit the corners, & so will the corners of the shower, would I use the adhesive as a sealant for the corners or how do I ensure a bond where there are seams? Secondarily, since you are in Canada and I am in NC, USA, are there any code applications here that would not be universally accepted or is this way above code and just best practice for those who don't like to do work twice? Thanks again! Very clear!

  • Shore grandmom Shore grandmom on Jun 08, 2018

    We've used the rubber liner in a shower a while ago. But a few years ago we fiberglassed 3 5x6 showers on the second floor of a million dollar house. I really liked the fiberglass it molds perfectly around everything. The fiberglass was installed part way up the wall and on the shower seats that were built in and tiled. I suggest having the fiberglass done by someone that knows what they are doing. As for the walls, you could paint a product like red guard on the seams of the cement board. It's like a rubber paint.

  • SimplyDesigning SimplyDesigning on Jun 11, 2018

    You can see how we did it here: You will need to prep your floor properly and we used a kit to build the slope etc in a non-standard size shower. It isn't hard, but you need to be exact.