Have a bathroom job coming up with a handicap roll-in shower.
I've lined shower pans before, but they had a curb. With the mortar bed contained in this small space, I didn't worry about the tile popping up. But now I need to line the entire floor up to the entry door.
Now I'm worried that a thin layer of leveler poured over the liner will crack up over time, but laying a thick mortar bed before thinset will cause a handful of problems from seating the toilet to being way out at the threshold.
I'm laying tile over a concrete floor, but underneath is the condominiums' parking garage and the shower drain is exposed, so I have to waterproof period.
How thin of a bed can you pour over a full-floor liner and still have it be crack free in fifteen years?
Is there an alternative?

Couple of questions first, and then we'll put together a plan over a couple of posts pack an forth, K?

1)Is there an architect on this job and if so, what was specified as that can cause some constraints on the materials that can be used.

2)What do you figure is the maximum possible height build up over the entire floor?

3)From the info in your post I'm guessing no plans to wall mount the toilet?

4)If the materials have been specified, can you get them changed? I ask this because to truly do this, you won't be doing a mud floor over the entire thing. As asked, the minimum thickness of bonded deck mud would be 3/4" but you wouldn't want just a flat 3/4" surface and a speed bump curb. An 1/8" per foot slope, for example, in the non shower area would be almost unnoticed but would create a bit of a drainage plane. You would not, however, want a flat on the slab that is covered with mud that is sloped as that is never the correct way to construct any shower pan ever (if you've ever seen it done that way, it was wrong and the biggest contributing factor to moldy and mildewing and stale smelling showers and also in violation of both IRC and UPC codes). In your case, you will want to use a surface bonded load bearing waterproofing membrane. If a pvc liner was spec'd, it ain't happening unless you want to be part of a mold remediation lawsuit.