Leaking WC to Soil pipe Tee joint - repair advice sought

[jkn]

Hi All we've had an 'off' smell in the bathroom recently, which I have managed to track down. There is a leak in the joint where the WC pipe joins what I think is a cast iron 'tee' off the soil pipe.

Image here:

This joint leaks perhaps 10ml each time the WC is flushed.

I have put a drip tray under as a temporary fix and to allow things to dry out, but I'm wondering about a proper fix. A helpful plumber who saw this photo seemed to suggest that the current use of liberal amounts of mastic was not a proper join in the first place.

What would be the best way to make good this joint once things are dried out, please?

Thanks Jon N

[newshound]

Your repair does not have to look pretty. In an ideal world you might re-make it. I think my inclination would be to put a layer of "original" Sylglas tape over the leak site

with a generous overlap. A 360 degree wrap would be ideal if you can get around the back.

[Tim+]

I think the ?proper? way to do it would be with one of these.

Your PVC section also looks to be made out of two different diameters of tube bodged together. In addition, there appears to be virtually no ?drop? along the length.

If possible, I think the best course would be to remake the whole connection from pan to soil pipe with a single piece of pipe with a bit more drop and using a proper PVC to cast iron pipe connector.

Tim

[Tim+]

Oops. Meant to say in addition, if it?s only started leaking relatively recently, I?d check for any partial drain blockage downstream.

Tim

[alan_m]

There appears to be two poor joints in that photo.

The plastic to plastic where the pipe bore increases and the plastic to cast iron. Repairing one joint may result in the other failing, especially if the repair mean moving a pipe.

Thee are a variety of fittings including the one already suggested from SF, and depending on what you are trying to connect.

video shows a variety of soil pipe connections

[jkn]

Thanks Tim, I was looking around and wondering if something like that should be used. So IIUC the 'finned' part goes inside the soil pipe end?

Is there any inherent flexibility in these sort of connectors?

Agreed on both counts ;-( . Certainly the soil pipe 'tee' is at a slightly different angle to the plastic piping

Yes ... I shall investigate a bit further when things have dried out. My preference would be to do things properly as you suggest, but there are some domestic acceptability factors to consider ("is it not done yet?!")

We looked for downstream blockages before I diagnosed the problem to here - I think we are OK on that front.

Thanks, j^n

[newshound]

Agreed, that's the preferred solution, but it might take time and a lot of people are busy at the moment. Connecting to cast iron can be a PITA, especially if it is very old. Mastic-based bodges are common (and often effective). The original would have been packed with greased string or hemp. Vertical joints were then finished off by casting lead (or perhaps solder) in the remaining gap. I'm not sure how angled ones were finished though.

[Tim+]

Yep.

Yes again. The fins will allow for a degree of fine adjustment but I wouldn?t chance too much angulation.

Tim

[The Natural Philosopher]

Silicone... Then more silicone... ...and even more silicone BTDTGTTS.

Just keep drying and adding silicone till it stops

[John Rumm]

Yup

A little bit.

They usually are - since the spur pipe will need a fall on it, that way the tee angle matches the (anticipated) fall on the pipe.

[John Rumm]

Quite often with a fillet of mortar. (and as you say with a string or hemp binding to stop the mortar getting past the collar of the pipe.