I have removed the leaking, ancient, shower tray from a bathroom to discover a large concrete block beneath it, ringed with brick. The underlying floor is concrete slab, it's a ground floor.
The alternative is to use a 900mm tray with a 760mm door, and build a false wall for the left hand side. (You can see - line of silicone & marks on the floor tiles - where the imbecile that did the original work built such a false wall - on the the WRONG side!)
I'll need about 90mm below the tray for a trap, this will just leave enough to get through the wall to a gully. It's all horribly tight.
Now. How do I get the concrete out? I've thought:
1) Hire a breaker - but I don't want to damage the underfloor, or the drain the runs right under.2) Drill many holes with SDS+ and then take it out in chunks.
3) Drill and cut at the parting line and then drive a chisel in with a sledge. I'm not sure if it will part with the floor though.4) Some other idea that I'm too thick to have thought of.
I'd welcome ideas. (I only have a 115mm Angle Grinder though).
R.