Leaking external soil pipe

[danielfitchie]

We've realised we have a decent leak in the soil pipe outside and we're wondering what the best way is to repair it.
You can see the leak in the video - when the toilet is flushed it spews out of the join between the plastic piping on the left of the leak and the cast iron on the right. I admittedly don't know much about this stuff but it looks as though the smaller diameter plastic pipe just goes into the iron pipe without any physical seal. There's a cm or so gap all the way round the plastic pipe with a bit of silicone just at the bottom which someone has put in at some point.
Id thought about just getting some decent sealant and pumping it full of the stuff but looking at the amount of water coming out, I wasn't sure it would do the job.
Thanks
Photo and video below:

https://photos.app.goo.gl/abqJxUpyhGCA17tq9

 

[Hugh Jaleak]

Check stack isn't blocked further down, does seem a lot of water to come back out. To seal, you can bodge it with putty, but personally I'd be looking at using a proprietary connector, e.g. a McAlpine DC-1. https://www.screwfix.eu/mcalpine-dc1-bl-drain-connector-black-110mm.html

 

[foxhole]

Agree needs replacing, anything else will be a temp bodge.

 

[undertrained]

How low down is it? Looks like you manage do to film ok or was it done from a ladder?

 

[danielfitchie]

Thanks for the replies. It's actually at ground level as our bathroom is downstairs.
Are the connectors easy to install? Would you just cut a small section of the plastic pipe and slot it into the plastic and the rubber into the cast iron? What would hold it in place? Forgive me lack of knowledge.

 

[Hugh Jaleak]

Finned end of DC-1 will push straight into cast socket. You'll need to cut the plastic section back a bit, take care as the plastic can become brittle over time, so use a sharp, fine tooth saw to do this. File the cut edge to give you a 45° chamfer, or you'll displace the seal in the fitting. I'd cut back enough to give you enough room to get a 'slip collar' in as well, or you wont get it all together. You will need the McAlpine DC-1, a 110m 'slip coupling' and a short length of 110mm pipe. (Screwfix do 1m lengths for £6)

So, measure up to see how much room you need. Cut existing pipe out and remove. Look at cast socket, ideally give the internal section a going over with a wire brush to get rid of any rust build up, then fit the McAlpine coupling, push it firmly home as far as you can get it. Now measure the distance from the internal stop in the McAlpine coupling to the cut end of existing soil pipe. Knock off 10mm, and cut yourself a piece of soil pipe to the length you've just measured. Now, lubricate the seals in both ends on the slip coupler and slide it over the chamfered end of the section of new pipe. Fit other end into the DC-1, and then line it up into position with the existing soil pipe, before gently tapping the slip coupling back up so it joins new and old sections together. Good idea to mark the halfway point on the new section of pipe so when you mark appears you know the coupler is halfway over both sections of pipe. Should be self supporting, if in any doubt, fit a pipe clip.

If you need a few tips on working with plastic soil pipe, found a video. (Other films are available, this was the first one I came across.)

 

[undertrained]

Failing that, opt for renewing your whole stack at that level.

 

[Hugh Jaleak]

Failing that, opt for renewing your whole stack at that level.

Be careful though when removing cast iron pipework, that any remaining cast above is adequately supported. It aint light, and if it comes down, it's not going to take any prisoners.

 

[undertrained]

Be careful though when removing cast iron pipework, that any remaining cast above is adequately supported. It aint light, and if it comes down, it's not going to take any prisoners.

Agreed, had a couple of near misses with that stuff.

 

[danielfitchie]

Really appreciate the advice will look into all that!