Raising floor to avoid slab disturbance

Looking to raise flooring (building platform) to accomodate moving drains etc... to swap tub and sink location in bathroom with slab foundation. What are the limitations? Could the tub be swaped end to end with a 4" subfloor.

That is such a bad idea from so many angles. Put the plumbing where it belongs.

The trap needs to be under the tub's drain. Without taking the old trap out, you can't run the output of one trap into that of a second one, plus, the depth of a trap and the required slope would require a higher platform. Tear up the slab and move things as required...works better and it won't look like an afterthought. Really bad idea to raise the floor.

Raising the floor is oh so handymanish!

floor

There are a lot of limitations and only a plumber at the site could define them for your job. The only time your idea would even be considered would be for a post tensioned slab that cannot be cut for any reason. And in that case a moving to a different house might be a wiser choice.