New shower

I will be redoing my shower in the near future. I currently have an acrylic pan with tile above, which was installed by the builder (1997). Floor construction is tensioned slab on grade. The plan is to use a Schluter pan & curb, and Kerdi drain with Kerdi fabric up the walls. I will probably end up tearing out all the old tile and whatever they used underneath, replacing it with 1/2" Hardiebacker and tile over the Kerdi. (I have John Bridge's Kerdi shower book)
My dilemma is the drain. I have no idea what to expect once I demo the old acrylic shower pan out. Would they have used sand or mud bed under the pan? What will I need to do to be sure the drain line will interface properly with the Kerdi Drain? I see lots of drain products, but few cross-sectional drawings that show what is probably under the pan. Any assistance is greatly appreciated. Thanks

First big thing is to verify that the drain line is 2", then whether it is ABS or PVC, since you'll need to specify the type when you order the drain.

There may or may not be any or enough room around the pipe... you won't know what is there until you tear the pan out.

Now, if you don't have enough room to mount the drain, or the pipe is 1.5" and not 2", then you could have big problems as messing with a post-tensioned slab can be really dangerous.

You only want to use the Kerdi in the shower...it sounds like you're considering it on the floor outside of the shower. There, if you want things waterproof (normally not necessary), you'd use Ditra and seal the seams with Kerdi-band. if you use Ditra, you don't need or want cbu on the floor. Sounds like you've been at www.johnbridge.com if not, check it out for your tiling and shower construction help.

That's the general plan. I will use Kerdi in the shower stall, and have already planned to use Ditra throughout the rest of the house. The development, at least Phases II & III have had many problems with cracks in the slab. I think at this point (1997 construction phase I) I am ok, as all my doors & windows work fine, and there are no cracks in the walls, but I would rather do a first class job on the floors rather than have problems later. The tile will a 5 tile porcelain pattern in the living areas and a 4 tile pattern in this master bath. I won't go cheap in the prep.
I just checked the shower stall and here's what I see. The Oatey strainer is locked firmly in place, but I could see down into the drain, and used a long stiff wire to determine the distances.
The ID of the PVC that I can see is 2".
3/4" below the strainer is the top of the PVC (white) drain pipe. It's surrounded by a thick black gasket that I suspect is part of the pan.
4 1/2" below the strainer is a junction of equal diameter PVC pipe. I can see a purple cleaner/solvent ring there where the ID's of the pipe meet.
9 1/2" below the strainer that is the water level.
13" below the top of the strainer is the bottom of the trap.



____________ top of strainer ___________pan

3/4"__________top of PVC surrounded by black thick gasket


4 1/2" __________ junction 2 lengths 2" ID PVC





9 1/2"______________water level




13" _______________ bottom of trap





As to the pan itself: <<Aqua Glass>> logo on the front. Measured on the outside from the top of the pan to the bathroom floor is 5 3/4"
Measured from the top of the pan to the top of the drain screen is 3 3/4" (I set a level on the front & back edges of the pan and measured straight down at the strainer). When I measure from the back wall to the center of the drain it's 18 1/2", and 17" centered from the right and left side walls.

It sounds like you need the PVC drain, and that there is at least enough depth to the trap so you can install the Kerdi drain. Now, as long as there is enough room around the pipe to fit the bowl and socket of the drain, you should be golden.

You can probably use an inside pipe cutter to cut the riser as high as possible, and still release the pan from the pipe, and once the edges are free, just lift it out and throw it away.

The alternative would be to use a sawsall or maybe a jig saw to cut around the drain, lift the old pan out, then trim things up so you can proceed.

You will need to address the cracks in the slab before tiling. If they have vertical elevation changes, you probably don't want to tile it. If it is just an expansion crack with no elevation change, then there are things designed to overcome them telegraphing through the tile.