I have 2in abs pipe coming up from a concrete slab for a shower. Unfortunately I am a beginner and put concrete right around the pipe instead of leaving some space for the drain to be installed. What should I do?

  1. Raise everything up by pouring more concrete everywhere? (I'm worried about the new concrete touching my non pressure treated framing)

  2. Chisel out the concrete from around the pipe? (I'm worried I might break the pipe)

  3. Find a smaller than normal drain that can fit inside 2in pipe. (I haven't been able to find any yet)


  • drill a circle of holes around the pipe to weaken the concrete, then chisel gently
    – jsotola
    Nov 6, 2023 at 4:17
  • Please post a picture. Nov 6, 2023 at 4:28

1 Answer 1


Option 2. Chisel a bit away from the pipe, and don't direct force at the pipe when breaking out concrete around the pipe. You can also make cuts with a diamond saw to make chiseling easier.

It's utterly normal to need to break concrete around DWV pipes. They are fairly tough, if you use reasonable care. If you screw up, break more concrete until you can get a coupling on with fresh pipe. If the concrete is freshly poured, get to it - every day, every hour you wait, it gets stronger, so the time to correct your mistakes with a fresh pour is as soon as possible, when the concrete is still weak.

Since this tends not to be as common knowledge as it should be, a graph of concrete strength gain [via damp curing - if the concrete dries out, it stops gaining strength; concrete sets and cures, it should never dry] in the early days:

Concrete strength age chart

Image source https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Ftse1.mm.bing.net%2Fth%3Fid%3DOIP.hBtGKqJmldyrb8KHFqmCFQE0DK%26pid%3DApi&f=1&ipt=99a4a4e2e11915cf584383d23226fab44afdf0d3c9b7eff13c8a62d322bb6a8f&ipo=images no endorsement implied

Note how fast it's increasing over the first week. It really makes a huge difference to get to chopping it as soon as you can.

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