A couple things to start. Our house is on a slab foundation, not in a flood plane or on a clay pocket that is settling. Also, we did a leak test in the shower prior to removing the tile and it does not leak. Now to the issue-----

We are re-tiling the step-down shower in our house and when we removed the tile on the floor we discovered that there isn't any of the slab foundation under the shower floor. (found this because we can actually see the dirt under the aweful mortar that they used to lay the tile.) There is some sort of white apoxy they used over the mortar probably used to waterproof the shower. Also, the shower drain basically has a strainer cap over the drain pipe without the normal pvc drains with the screw on strainer that I have seen in other jobs. My question is.....since there isnt slab foundation in the shower floor should we float concrete over what is there, install an acutal drain to the pipe, and apply a topical membrane before we tile the shower? My logic is telling me that is the best solution since that will create a sound floor beneath the shower, also bonding the sides to the slab. Any help would be appreciated!!!

 

I'm unable to get a visual in my head, of what exactly is a "step down" shower. Possible the attach a picture? http://www.doityourself.com/forum/el...-pictures.html

 

I will get some good pictures in a bit but it basically means the shower floor drops about two inches down from the bathroom floor. Hopefully that makes sense. I'll post pictures in a bit.

 

Was the drop down shower floor original to the house? I'm wondering if someone tore out the old shower floor and slab in order to lower ..... and didn't know/care what they were doing

btw - welcome to the forums!

 

Hopefully I uploaded these correctly.

 

Marksr, that looks to be exactly what they did. So, what is th best way for us to proceed before we toe to make sure the floor is sound beneath the new tile?

 

That's a little bit out of my area of expertise but I'd excavate it some, make sure the drain is where I want it and pour 3"-4" of concrete. Some of the others should have more/better info for you

 

Looks like you had a breach of the mopped on pan liner that caused some erosion. Unfortunately, you are going to have to remove a good portion of what is there to rework the drain. Once open, you can look closely at what you have and begin to rebuild. As Marksr mentioned, you want a good base to begin the rebuild of the area. You will want compacted soil, 4" of cement and then a mud bed on top. You can also get yourself to a flat pad and come back in with a pre-formed shower base and a compression drain body before you tile the walls. The second option will be the easier of the two.

 

Not an expert either but around here with shifting soil common I'd be worried if the new slab wasn't tied to the old slab to keep it from moving up and down. I'd consider fastening metal straps to the edges of the existing slab then bending an ell on them where they were embedded in the new pour. Maybe run the new pour a couple of inches under the existing slab so it wouldn't float up.