Soil pipe leaking

danrv

Hi
I'm just fixing a soil pipe leak for someone. The pipe was renewed about a year ago and then the white waste pipe added later when the bathroom was refitted.
There was loads of silicon bunged around the join which I've now removed.
Hoping to do a temporary repair with silicon so the suite can be used. 
Just wondering if a new section could be fitted in from below.
The area shown is the hallway ceiling.
Any help appreciated.

sheenas

Looks like the strap on boss has broken. Simple case of replacing the strap on boss and removing the stress on the joint due to the angle of the incoming pipe.

WIAWSNB

Which specific part are you asking about? 

danrv

WIAWSNB said:

Which specific part are you asking about? 

Just figuring out really how it's been done. All the silicon added didn't look right.

danrv

sheenas said:

Looks like the strap on boss has broken. Simple case of replacing the strap on boss and removing the stress on the joint due to the angle of the incoming pipe.

Good point. The strap appears to be ok but it's not pulled together.

WIAWSNB

sheenas said:

Looks like the strap on boss has broken. Simple case of replacing the strap on boss and removing the stress on the joint due to the angle of the incoming pipe.

Ah, I see.
For the boss to clamp properly on to the 4" waste pipe, I think the large grey pipe needs to be rotated, so the white waste pipe meets it straight on.
If the large grey pipe is solvent welded on to the black soil pipe, as it looks like, then the whole black pipe might need rotating slightly It's all a bit weird.
Does that make sense?

danrv

WIAWSNB said:

sheenas said:

Looks like the strap on boss has broken. Simple case of replacing the strap on boss and removing the stress on the joint due to the angle of the incoming pipe.

Ah, I see.
For the boss to clamp properly on to the 4" waste pipe, I think the large grey pipe needs to be rotated, so the white waste pipe meets it straight on.
If the large grey pipe is solvent welded on to the black soil pipe, as it looks like, then the whole black pipe might need rotating slightly It's all a bit weird.
Does that make sense?

The grey pipe doesn't fully go around the black pipe. Not sure why it's there.
A cable tie was used as an attempt to pull the boss clamp together. There's a gap where the white pipe inserts into the black one and it's been filled with silicon. 
This is where water is leaking from.

WIAWSNB

danrv said:

It's not clear to me what's going on with these parts. But what is pretty obvious, I think, is that the 'problem' is caused by the white pipe approaching at the wrong angle - it should be going centrally into the black pipe.
I'm trying to work out if the smaller round grey collar was originally part of the larger grey section? Does it look as tho' they were a single part that broke off? 
See the curved end of the small grey collar, does that have a black rubber gasket on it? Hard to tell. 
Your trouble seems to be poor access? Where does that white pipe go? Can it be moved? Temporarily removed? Where does the black pipe keep going to? Can it be rotated?
Could you break away a bit more of the ceiling to expose more of the white pipe?
Two possible ways to sort this, I think. One will rely on the white pipe having some sideways movement so it could be moved to enter the soil pipe centrally, as it should. Then you either rotate the black soil pipe to suit, or you chisel off that grey sleeve from the black pipe, clean up the surface enough to solvent a new boss back in place - in the correct position. 

WIAWSNB

Or, you cut that white pipe, add a 45o elbow to let it enter in the same place as current, but at the correct angle, and then fit a new strap-on boss adaptor.

danrv

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.

WIAWSNB

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.

Can the white pipe be withdrawn - is there backwards movement? If so, that would allow access to the problem area, and even allow the joist hole to be elongated slightly sideways.
Without this, your options are limited.
I presume there is no movement in the black soil pipe either; nothing sideways, and also cannot be rotated, even a small amount?
The issue was pretty undoubtedly caused by the installer, when they got the pipe alignment wrong. Your options would appear to be to either correct this (seemingly very difficult), or to re-bodge it as currently, but doing it better. Ie, either prising the old boss back into place at the same tensioned angle, fixing it using a stronger method than before, and with a better sealant than silicone, or, fit a new boss. 
For the latter solution, you could likely fit a boss collar like below to the existing grey plate, solventing and clamping it into place.

Then I'd be inclined to ditch the usual rubber gasket, as this will always be significantly distorted by the incorrect approach angle of the white pipe, and keep applying unwanted pressure to dislodge the boss. Instead, backfill around the pipe with something like StixAll or similar*, to replace the gasket. All surfaces made fully clean and lightly keyed first.

Unless you can add an elbow to that white pipe, but it doesn't look like there is enough room.

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).

*Not sure what the best 'rubber' substitute would be.