I'm not understanding exactly what you mean to do either, Shelley. When I pour SOG with shower, I drop the shower area 5 1/2 inches (one 2x6 for simplicity of forming). I leave a standard box-out with the drain pipe roughly centered. That allows vertical room for a pre-slope, liner, and mud floor and room for about a two inch step-down and no curb.
But you've still gotta make provisions for the pan liner to run a few inches (at least) above the bottom of your wall framing. Or you could just make the pre-slope and use the Kerdi system.
In any event, you must make provision for the installation of either a clamping drain or a Kerdi drain, and trying to do that successfully as part of the slab pour is gonna be real educational for one of us.
It is so much easier to provide a drop and build it back up where you want it, with the necessary slope and finish. If all you need is the pre-slope and Kerdi, your drop would only need be 1 1/2 inch or so if you want the shower floor to be level with the bathroom floor at the door. But there's still the matter of the waterproofing.
Now, if you plan the shower to be so large that water will never reach any of the walls, and you don't care where water might go if the drain ever backed up, and you don't care if a little water leaks down into the ground where the drain is, and you want it all to look like the same floor, you can do what I think you're suggesting. I'd slope the entire floor (or most of it) to a regular floor drain in that situation. Only place I've ever done that is in an upscale greenhouse. Stained the concrete floor and called it finished. Looked nice. Works fine. But it's not living space, either, and don't nobody care where extra water goes on accounta water goes
everywhere in there.
My opinion; worth price charged.
Curbless Shower
