Cast Iron to PVC connection - Sewer Line

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by manna, Jan 6, 2011.

  1. manna

    manna New Member

    Jan 6, 2011
    Chicago, IL
    Replacing part of horizontal cast iron sewer line that is sagging. A few questions here.

    Is it possible to cut out the sagging Cast Iron section and replace with PVC?

    Is it possible to have the line go Cast Iron to PVC and then back to Cast? Do they make couplings like this?

    Would I be better replacing the bad cast Iron with new cast?

    This section is under concrete slab.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    Chicago might require cast iron, so check that first. Otherwise, underground, you can use a Fernco fitting. This is essentially a thick rubber sleeve with screw clamps at each end. It requires that you torque them properly and backfill and support the line properly, but are approved for use underground. What caused it to sag? Make sure when you replace, you don't end up with the same problem!

    Another possibility if you can remove the pipe from a hub, is to use a Fernco donut. This is inserted, then the PVC is pushed inside. The rubber compression makes the seal. Sizing these for proper fit is critical. This might take care of one end, and the sleeve on the other. Just depends on what you have, and where it is.
    Last edited: Jan 6, 2011
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  4. manna

    manna New Member

    Jan 6, 2011
    Chicago, IL
    I'm assuming its a bad connection that just got worse over time with ground settling. Had a camera down there and its about a 10 foot belly, and had it marked. Won't know fully of the cause till its dug up. Hiring a plumber to do all the pipe work, but will be doing the demo myself. Just wanted to know if this something like this was possible, thanks for your reply.
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