existing cast iron pipe into clay pipe

I want to install a toilet and replace the existing 60mm cast iron pipe with 110mm pvc

It looks as if the cast iron has been cemented into the clay pipe junction

I’m trying to avoid replacing the clay junction as it is shared with four other properties

I’m thinking of drilling holes into the cement around the cast iron to remove a plug of cement leaving a hole large enough for the 110pvc

Does this sound sensible?

  • 4
    Just looking at that clay wye and thinking about replacing that 60mm pipe scares me. Whatever you decide to do, have a plan and be prepared to deal with that wye cracking.
    – JPhi1618
    Nov 2, 2017 at 21:04
  • On the cast I have worked on the fitting is usually packed with okum and then sealed with lead. If only clay it may be an easy job but expect some cloth like material that has been packed using a dowel and hammer (very tight) to be under the clay seal.
    – Ed Beal
    Nov 2, 2017 at 23:24
  • If you do tackle this, have a good plumber's number handy. I'm not even joking.
    – Valkor
    Aug 8, 2019 at 20:29

1 Answer 1


I would probably either keep a stub of cast iron and connect the pvc to that or cut out the wye and put a pvc wye there instead

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