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I can use existing plumbing lines to make a bathroom and why black pipes are inside white pipes

  • Welcome Richard. You need to add much more detail for "i can use existing plumbing lines to make a bathroom" In order to get an informed answer it is best to provide as much info as you can and have specific questions.
    – Alaska Man
    Mar 7, 2020 at 22:47

2 Answers 2


Expanding on Ed's answer. When drainlines are encased in concrete the sleeve protects them from damage during construction. There's usually a lot of equipment or heavy material being moved around and you don't want them damaged. They're tough to repair if broken at the floorline.


I believe this is a bathroom rough in. I also sleeve drain lines many times if just roughed in, the 3 inch is for the toilet and the 1-1/2 for a sink, if there is a 2” it is normally for a shower or this is how I plumb them.

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