Best practice for sealing leaking joint - soil stack

[foxoles]

Hi guys,
Got a leak from a joint - bathroom sink pipe to soil stack.
Access is only from below, unless I want to make a hole in a tiled sloping roof.:nono:

Pipe is a combined sink and bath - sink pipe comes through a breezeblock wall and there is no side to side movement, so the pipe is in a fixed postion. Leak is not massive, but has stained ceiling and got mould growth on plasterboard.

Seems that the rubber sealing ring has just pushed out a bit - best practice solution? Pull it back up the pipe and clean it, push it back in? Add silicon sealant to it before pushing back in? Add Plumbers Mate to outside of sealing ring?

Cheers
Jonathan





Additional info - toilet waste pipe attaches above the leak, and when flushed pours out of joint.

This stack has an air admittance valve.

 

[Stigster]

I would pull the pipe out, clean up that boss connection, clean the end of the pipe and replace that rubber boss adaptor with a solvent weld-compression boss adaptor as they are generally more reliable than the push in rubber type you have failing you there.

https://www.plumbingforless.co.uk/p...ompression-boss-adaptor-92deg-32mm-grey-sn66g

Measure the waste pipe as it might well be 40mm so buy the correct size boss adaptor for your pipe.

The only thing I am not certain of is the material that black boss is made of and whether it is suitable for gluing. Hopefully someone here will know and comment.

 

[JCplumb]

Agreed, although the 40mm that goes into the boss isn't solvent pipe, it would need to be replaced with solvent pipe which would also mean replacing the tee with something like a McAlpine multifit tee, which looks like it would require an inch or two chipping out of the block where the horizontal comes through to get the required wiggle room.

 

[JCplumb]

Ooh, just re-read your post, yeah a solvent weld compression boss adapter would be just the ticket. Still gonna need some wiggle room though.