Soil pipe leaking

danrv

WIAWSNB said:

danrv said:

WIAWSNB said:

Where does that white pipe go? Can it be moved? 

The white pipe emerges through a hole in a joist. No sideways movement possible. 
The ceiling can be cut away for better access.

Without being able to fully withdraw that white pipe, you are going to find this a very awkward task, as it looks as tho' it's going inside the black soil pipe? So, unless you can fully withdraw that pipe from the other end, I would remove another section of roof to expose the white pipe beyond that joist, cut it in the middle, and then the end section can be withdrawn. It can be rejoined using a union when the job is finished (solvent type usually best, as long as the pipe size suits).

Yes, the white pipe goes inside the black one but it's not a good fit.
A lot of silicon was used to fill it but it didn't work. It's a bit of priority job as the new bathroom can't be used.

Agree, the best bet would be to remove a bit more ceiling and cut, remove and fit another piece of pipe. 

WIAWSNB

The white pipe is not a good fit because it ain't straight on the black pipe. Another piece of pipe is not going to help unless the approach angle is changed.
The only reason to cut the white pipe further along is so you can withdraw it to allow access to the 'bodge'.
So, a bit more ceiling cut away, and then cut the white pipe in the centre of its length in-between the next two joists. That will allow it to be rejoined afterwards with a union.
Extract the white pipe end. Remove that loose boss. Clean up what's left. Have a good look at what you have there. Measure the size of hole in that grey panel.
Is that grey panel fully secure? Ie, has it been solvented in place, with zero trace of water getting out between it and the black pipe? 
I'll ask again - is there any possibility of rotating that black pipe, even an inch?

WIAWSNB

Where does that black pipe go as it disappears in your photo?
Anyhoo, please post pics once the next ceiling part has been removed.

danrv

WIAWSNB said:

is there any possibility of rotating that black pipe, even an inch?

I did try briefly but it didn't budge. It goes into a round base in the floor. The loo pipe is attached further up. It's all neatly boxed in.

danrv

WIAWSNB said:

Where does that black pipe go as it disappears in your photo?
Anyhoo, please post pics once the next ceiling part has been removed.

It goes up into the bathroom and out through the roof. It's actually at my bro's house, forty mins away so I'm not able to easily do the job I started doing.
A plumber is hopefully going to take a look otherwise I'll pick up where I left off.

Section62

danrv said:

WIAWSNB said:

is there any possibility of rotating that black pipe, even an inch?

I did try briefly but it didn't budge. It goes into a round base in the floor. The loo pipe is probably attached further up.

Unless it is solvent-welded at the bottom, if it has been there a while the rubber seal on the lower socket has probably become quite firmly attached which would make it difficult to turn the pipe in the socket.

Plus it is quite difficult to get a good grip on a 4" round pipe with bare hands.

A strap wrench would give you more leverage to rotate the black pipe, but it needs to be done with care to make sure nothing else gets damaged.

You should really try to get a replacement boss with a proper rubber seal rather than trying to bodge it up with silicone or anything else which comes in a tube.

The other issue you've got is it appears the white waste pipe is protruding into the stack pipe which means any solids/paper coming down the stack pipe may get caught or snagged by the waste pipe.  That could result in an unpleasant and difficult-to-clear blockage.  A boss connector and proper rubber seal should prevent the waste pipe going in too far and risking this problem.

danrv

WIAWSNB said:

Is that grey panel fully secure? Ie, has it been solvented in place, with zero trace of water getting out between it and the black pipe? 

I don't think water is leaking out of the join between the grey panel and black pipe.
Would be easier if it came off to see where the white pipe goes in and the condition of the hole.
If the black pipe can't get twisted, a section of the soil pipe will need to be cut out to position a hole in the centre. 
Probably not possible without distrupting the bathroom tiling/boxing in.
As it is, a strap boss is a bit useless as the ends don't pull together enough and doesn't fit flush.
It may be a case of trying to get a new piece of white pipe to fit snug in the offset hole and use maybe a polyurethane sealant or solvent weld.

Section62

danrv said:

As it is, a strap boss is useless as the ends don't pull together enough and doesn't fit flush.

Yours looks like a bolted type, which means the ends should never touch anyway.

I'd guess the 'grey panel' is a section of pipe someone has cut to size and sprung open to fit snugly on the black pipe, presumably because the black pipe underneath has been damaged or had an oversize hole drilled in it.

The problem with this is the effective diameter of the grey section is larger than the standard 110mm (nominal) - which means a strap boss will never fit properly because they are designed to work with a 110mm (nominal) pipe.

TBH if it were me I'd bite the bullet and cut this section of pipe out completely and start again.  Whatever you do to try to fix it will still leave you with a degree of bodginess and risk of leakage.

If a new section of pipe were inserted in the main stack, the hole for a new strap boss could be made a bit lower - which would then open up the possibility of using some 90/45 elbows to connect the white waste pipe without it being force fitted and stressed.  (this may require the boxing in to be enlarged a bit at the top)

danrv

Thanks for the replies.
Managed to get a plumber to do it all properly. The bath waste pipe was also badly fitted at the plug hole so that's been redone.

grumpy_codger

danrv said:
... 

Managed to get a plumber to do it all properly.... 

A photo? Jus curious if this proper job is what I thought it had to be...