Seal soil pipe joint internally

Discussion in 'Plumbers' Talk' started by Jonathan Frost, Feb 24, 2017.

  1. Jonathan Frost

    Jonathan Frost New Member

    Hey guys, I've recently replaced my toilet, the new one has a waste pipe slightly lower than the previous. I used a flexible connector and although the waste has to go uphill slightly the toilet clears. I noticed a day after however that the wall to one side of where the soil pipe enters the wall is damp. I removed the toilet and it seems a bit of waste remains in the waste pipe/soil pipe connector, looking down the soil pipe there appears to be a join about 20cms in to the pipe. Do you know of a way to seal this joint internally to stop any leakage in to the wall? The joint occurs within the wall so I cannot seal it externally.

    Cheers for any help guys!
  2. CGN

    CGN Well-Known Member

    Is it plastic pipe? If so, bite the bullet and fit a compete piece to the stack/elbow etc...not too hard, just a bit of cursing and you'll never have to do it again! :)
  3. Jonathan Frost

    Jonathan Frost New Member

    Thanks for replying, no it's a cast iron stack unfortunately. I can see the join so hopefully can find some waterproof gunk to spread on it.
  4. CGN

    CGN Well-Known Member

    Pity. Ok, is it a cavity wall?
  5. Jonathan Frost

    Jonathan Frost New Member

    Solid wall
  6. CGN

    CGN Well-Known Member

    Ok. just to clarify, does the cast iron come all the way through into the house or finish 'half way' through wall?
  7. Jonathan Frost

    Jonathan Frost New Member

    Well a cast iron pipe comes half way through the wall (from outside) and then seems to have another iron pipe connected in to it in a compression fitting manner. This short pipe is then connected to the toilet by a flexible connector.
  8. CGN

    CGN Well-Known Member

    Ok. Well chances are, you ain't gonna separate it.


    1. Replace stack with plastic.

    Need a tower, ideally a helper and a spare day. Not a job I particularly enjoy, but at least you'll know it ain't gonna leak...ever again!

    2. Clean out the joint as best as possible, and use some CT1 or similar to seal it. Then fit a cast iron to plastic adaptor and put a sleeve of 110 plastic in this. You'll then have a really good water tight seal for your flexi.

    I'm sure others will advise and help. :)
  9. Jonathan Frost

    Jonathan Frost New Member

    Thanks for the reply, going to try and dry it out, seal the joint as best I can with ct1, btw is there an equivalent available in store, only seems available online. I'm putting plywood down and then tiling, hopefully this will raise the waste pipe enough to clear properly.

    Thanks again!
  10. CGN

    CGN Well-Known Member

    Strangely enough, I popped into EH Smith builders merchants this morn and whilst waiting, a lady approached me who was promoting hippo pro3. Basically a competitor to CT1. Gave me a free tube to try :)

    Others may have a better/different solution Jonathon, hold tight for a few hours :)
  11. Glad its Friday

    Glad its Friday Active Member

    CT1 available at City Plumbing.
    Lubricate up any plastic bits before assembly with silicone spray so they slide together nicely. Under NO circumstances be tempted to use fairy liquid - it attacks the rubber seals and will cause failure a few years down the road....

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