Need advice: Replacing 1.5" drain pipe buried in 4" slab, pipe is tight against the bottom of slab

[samuelaz]

Hi everyone,


I’m in the middle of a DIY bathroom drain replacement project and ran into a problem. The 1.5" drain pipe runs under a stud wall and is completely embedded in the concrete slab — it’s actually sitting right against the bottom of the slab (about 4" thick). and also under a stud and the bottom plate.


My current plan is to:

• Cut and remove a small section of the bottom plate (not the studs) to get access.
• Break open the slab to remove the old pipe and replace it with new.

The problem:

• The slab is extremely hard (lots of aggregate, maybe high-strength concrete).
• There’s no space to use a large concrete saw or cutoff saw in this area.
• The pipe needs to be fully replaced, but need to not break the vertical main drain.

the pipe goes to this main drain.

1.5" pipe right next the slab


My questions:

1. Any tricks to make the job easier or faster?
2. Anything I should watch out for when working that close to the bottom of the slab?
3. is the tee for 2 inch pipe? seems like the 1.5 inch pipe is in a reducer, but I am not 100% sure.
   

I’d appreciate any tips from those who have done similar work in tight spaces without damaging the studs.


Thanks in advance!