I am buying a building that sits on a concrete slab but plumbing was not run first. I’m going to build a bathroom, should i saw cut the floor and run plumbing under the slab or have you ever ran toilet , shower, sink above the slab , in the walls ?

Toilet above slab, you would have to build a platform to elevate it from the slab. The big 3" or 4" sweep is going to need some room. Then vent stack inside the wall, and you could pop it out of the top of the wall horizontal. If it is a well made slab, with beams in it, cutting could be pretty much out of the question, since the beam would seem like it is halfway to China if you try to bust it out. If it is a slab that is only 3 1/2" to 5 1/2" thick, you could cut out a square with a big gas powered circular saw then excavate.

You could excavate next to the slab outside to learn how thick it is at the outter wall where you need plumbing to come through. That would decide for me which route to take.

They also make toilets with grinder pumps built in to the back of them that allow for a lav drain to be plumbed in the side. The shower would have to be built up to allow for drainage to said pump.


https://www.saniflo.com/us/installing-a-toilet/69-sanibest-pro.html

Just now learning of the macerator idea - pretty cool

They do make back flush toilets

Yes, the benefit here is that you can pump everything via 1" pvc with the ability of moving the waste to an existing drain without cutting concrete or manipulating existing plumbing.

Good suugestions so far.

I have saw cut a moved tub/shower drain. As mentioned, be care not harm structual integrity of slab. Any concrete repour needs to have rebar driven into existing remaining slab.

I have a back flushing toliet. Looks and works like a standard residential unit.

Also as mentioned, sanitary ells are long radius sweeps. Pressures ells are short radius. Two different animals.

Only experience I have had with macerator pumps were lift staitons. As anything, if doesn't get cycled often, life expectancy is short.

Best avenue may be a combination of slab cutting, floor elevation and a unconventional toliet.

First make sure your slab is NOT Post Tension, structural cables in concrete. I would have the slab scan to show where the beams are at and if Post Tension. There are companies that do this.