Cast iron soil pipe to cracked clay sewer pipe issue - repair or replace?

[Richard Waight]

Hi all, was hoping for some advice from the forum.
Getting a new patio done and while excavating around the sewer pipe I noticed that the clay collar around the cast iron soil pipe was cracked and leaking. (which explains the damp we've been getting on the inside wall)
My dilemma is now weather to pull it all out (including the clay gully etc) and replace with plastic which is a fairly big job. Or as I've read, just repair the collar which is 90% still there and fill in gaps with clay and then cement all around it.
Would really appreciate any thoughts here.

Cheers

Rich

 

[Hugh Jaleak]

Replace, I doubt you'll get that to seal properly, and if you do, any slight movement will crack it again. You've done the hard work, digging out to expose what's there, I'd cut it back as far as you can, being that close to the house, as replace as much as possible.


Gulley is rather close to the stack connection, but if it's worked all this time, it shouldn't be an issue in future.

 

[Richard Waight]

Thanks Hugh, kinda what I was thinking but just wondered if a repair job would have been possible and perhaps just as effective.

Is it the same Hugh Jaleak on Garden Law? I'm SwitchRich on that site in case it is

 

[Ian H]

I'd redesign it slightly like this:

 

[Richard Waight]

Thanks Ian! Could you tell me why it would be better like that? I.e. as I see your diagram you would put the gully drainage pipe into the new soil pipe after the new join with the vertical cast iron soil pipe?
I'm assuming here you would replace instead of trying to fix?
Cheers for your help!

 

[Hugh Jaleak]

I am one and the same.

My concern about making a rigid repair, such as you propose, is it will not allow any movement. The reason it has broken in the first place is likely to be ground movement, making another rigid joint and you'll probably find it's leaking again before long. Replacing with new pipework will introduce some flexibility into the pipework, and prevent further problems in future.

I see what Ian is trying to achieve. Building Regs ask for a long radius bend at the foot of a stack, simply to slow the falling waste down when it hits the bottom, and send it on its way along the drain. Fitting a Tee like that could cause issues with waste splattering everywhere when it hits the bottom of the pipe and possibly backing up into and blocking the gully.

Joining the gulley downstream of the soil pipe will allow use of the appropriate bend. If you use a bottle gulley and a couple of 45° bends to kick the gulley drain out around the soil pipe, it'll be easy enough to clean out in future, should need arise.

 

[Nige F]

That gulley is 19th Century with the wastes inches away from it - go with Hugh's bottle gulley and put the wastes through the grid

 

[Richard Waight]

I feel enlightened!
Thanks so much for sharing your wisdom Ian, Hugh and Nige. I've never pictured a turds g force experience as it makes its way down the pipe. A hard splat does nothing for momentum... lol
Will put a long radius turn at the bottom of the cast iron soil pipe and then attach the sink and bath waste via new gully into the horizontal section.
Will make sure I update the forum with the proposed end result.

Cheers


Rich

 

[Ian H]

What's there could never have been great, a T would point too far left and a Y too far right. If there wasn't quite so much fall on the pipe you would get paper in the gully when you flush.

The hardest part of making a repair would be getting a nice cut on the clay, the rest is straightforward with push fit fitting and jubilee clips on the rubber clay to plastic (ac4000) and plastic to cast (dc115).

 

[Hugh Jaleak]

May have to trim a bit off the bottom of the cast to accommodate a rest bend, angle grinder, (wear eye protection!), will soon cut through that.

Make sure that cast is adequately supported, it's bloody heavy and if it hits someone on the way down it wont be pretty.

 

[Ian H]

I'd use a tighty 90 and leave the cast. They are less tight than most clay rest bends and much better than your current set up.

They have a plain end too that looks like it would be perfect for under your cast.

 

[dilalio]

I feel enlightened!
Thanks so much for sharing your wisdom Ian, Hugh and Nige. I've never pictured a turds g force experience as it makes its way down the pipe. A hard splat does nothing for momentum... lol
Will put a long radius turn at the bottom of the cast iron soil pipe and then attach the sink and bath waste via new gully into the horizontal section.
Will make sure I update the forum with the proposed end result.

Cheers


Rich

Everyone knows the expression "when the sh!t hits the fan" but few think about it hitting the bottom of a stack!

 

[bobasd]

jjust sayin but if the gulley is redundant then remove it, cut the CI soil pipe and tie-in the waste and down pipe to a new bit of 110mm plastic pipe with a boss/access fitting with a slow bend connected to the salt glaze.
just a thought

 

[rsgaz]

it hitting the bottom of a stack!

If only all waste pipe was transparent, me and other non-plumbers would all have a much better understanding of the effects of swept bends, fall, etc and be a lot more careful about what gunk goes down the sink, too!!

 

[Richard Waight]

I submit my work for peer review... lol!
I also had my builder pal Shaun over to help and to be honest he made most of the big decisions but I think they were all inline with the suggestions of the forum which is awesome. Drains back and functioning again which is great news. Just wanted to post this for interest and also to say thanks very much to you all for your help!

Also spotted what I think is a water pipe which comes into my house at the side and returns at the back of the house and runs (i believe) along the back of the terrace. Any ideas here on what it is made from? I'm thinking cast iron but worried it could be lead. The house is just under 100 years old and I've no idea what was used at that time of building, or in the case of its existence if anything has been renewed. Pipe pressure is great so not looking to fix a non problem.