Leaking soil stack

[craig51]

Ok, noticed a small damp patch forming on my ceiling over the last week.

Went upstairs, looked all around the obvious culprits, like the bath, sink and toilet. All are sound and dry.

So i ripped up the floor in a small cupboard next to the bathroom, and found where the toilet enters the soil stack, and it heads downstairs.

As it heads downstairs, there is a double 45degrees bend, as it needs to bypass the downstairs kitchen wall. The leak is coming from that bend!

As such, it is in a VERY tight location, and the only way to get it out would be to either remove the celing downstairs, or bathroom tiles upstairs. There is also some CH pipework nearby making access even harder!

Usually I would of had it removed, seals inspected, cleaned and put back in, but as this is not possible, its plan B, as in BODGE!

I was able to just get my finger in and smear silicone sealant all around, so I am hoping this will be the end of it. If not, does anyone know if the spray n seal stuff you can buy is any good. Or, just cover the whole thing in spray foam.

The leak is very small, maybe one drip a minute.

As I said, if I could do a proper job I would but its not possible without a load of work and destruction, and all for a very small leak.

Any advice much appreicated.

 

[doitall]

A proper plumber would have used gap cement, if you could get it dry.

 

[cmother1]

Is the leak coming from one of the seals or a crack somewhere in the pipe or fitting? If it's the former I think I'd try to tape it somehow. Denso tape is an old standby, but I'm not sure how it would react with PVC pipe. The goo on it is oil based, so, I suspect, not very well.
Here's another from my "classic bodges" collection. If you can get hold of an old butyl rubber bike inner tube cut it into 1.5" strips and use it to bandage the leak. You have to stretch it hard as you go, then finish it off with PVC tape to stop it slipping. I've used this system to temporarily fix all sorts of things - nail through heating pipe, cracked lead sink trap, leaky washdown gasket, etc.. It works very well.
If it's a crack in a fitting I'd try to stick a patch over it made from a bit of soil pipe.
I think I'd check on how bad the leak is also. Watch it while someone flushes the toilet. You might find it's putting out a lot more than 1 drip a minute.

 

[craig51]

i beleive its a gap in a seal. Hopefully the silicon will seal it, but we will see.

Re the innertube idea, this sounds good, but there is no room to get this in place, and directly below this soil stack bend is a joist also!!!

I will give the spray can a go if that fails. If that also fails, then spray foam.

If that fails, then ripping off the ceiling or floor.

 

[cmother1]

Sounds like a cack-handed plumber hasn't de-burred the pipe adequately and has mangled the seal putting the fitting together. Whatever gunk you use try to get the pipe really clean first - something like cellulose thinners to de-grease and clean it (but not white spirit).
Good luck. This one sounds like a right b*gger.