leaking downpipe repaired with mastic tape

clive0510

JGB1955 said:

clive0510 said:

 you dont want someone else's waist water on your roof! speak to your neighbour, tell them its not really good enough.

Lots of people harvest grey water for their garden.... black water is a totally different kettle of ****!

it still has to be fixed regardless of what it is.

starving_artist

clive0510 said:

so to be clear, your neighbour has had some work done which involved having said pipe fitted or replaced. and now its leaking their waste over your roof. 
firstly who ever did the job must of been good, if they can't install a simple waist pipe. 
secondly its got to be fixed. you dont want someone else's waist water on your roof! speak to your neighbour, tell them its not really good enough.

It is not leaking at the moment.  I just don't see that mastic tape lasting and when it fails it will leak over my flat roof.  The neighbour knows and is getting the roofer to come back but given his idea of a fix was the mastic tape I think we are going to have say how we expect it to be repaired.

Jeepers_Creepers

Who installed this pipe in the first place? That is taking grey waste water from their bathroom?

It does look like what you describe it as - an actual 'downpipe'. Ie, a 3" pipe designed for rainwater goods. It is not a 'waste' pipe which is typically less than 2" diameter, has sealed pipe fittings and should end up PDQ in a nearby 4" soil/vent stack.

This seems to be  an incorrect installation, and the fact that it leaks - which is no surprise since downpipes don't tend to have seals on their connectors - is almost a minor point. With such a long and torturous route, I'd be surprised if they don't suffer from a lot of trap 'gurgling'. 

Who installed this?

starving_artist

Jeepers_Creepers said:

Who installed this pipe in the first place? That is taking grey waste water from their bathroom?

It does look like what you describe it as - an actual 'downpipe'. Ie, a 3" pipe designed for rainwater goods. It is not a 'waste' pipe which is typically less than 2" diameter, has sealed pipe fittings and should end up PDQ in a nearby 4" soil/vent stack.

This seems to be  an incorrect installation, and the fact that it leaks - which is no surprise since downpipes don't tend to have seals on their connectors - is almost a minor point. With such a long and torturous route, I'd be surprised if they don't suffer from a lot of trap 'gurgling'. 

Who installed this?

Must have been done when the house was converted in to flats.  They just ran the waste pipes in to the downpipe.  Didn't realise that about rainwater pipes not having sealed connectors.

What would you recommend?

Jeepers_Creepers

What to recommend? I dunno...

The leak isn't down to a 'fault' with that pipe, it''s just that the fittings - elbows etc - simply slot loosely together. The reason that one is leaking is due to the too-gentle slope it's on - water is flowing down that pipe 'sideways' so some of it backs up through the normal gap in the fitting (these elbows are usually fitted to vertical pipes, so the water cannot go back 'up' to get out).

Although it's 'wrong', who will you get to make it good - ie redo the whole thing using a new soil stack and proper waster pipe? I doubt that's going to happen (unless you bring it to the attention of the local planning dept...)

That joint can be sealed 'properly' using something like Stixall; the fitting would need pulling apart and the insert coated with a suitable sealant before refitting. What's been done is only a poorly-applied smear on the outside of the join by the looks of it. 

starving_artist

Jeepers_Creepers said:

What to recommend? I dunno...

The leak isn't down to a 'fault' with that pipe, it''s just that the fittings - elbows etc - simply slot loosely together. The reason that one is leaking is due to the too-gentle slope it's on - water is flowing down that pipe 'sideways' so some of it backs up through the normal gap in the fitting (these elbows are usually fitted to vertical pipes, so the water cannot go back 'up' to get out).

Although it's 'wrong', who will you get to make it good - ie redo the whole thing using a new soil stack and proper waster pipe? I doubt that's going to happen (unless you bring it to the attention of the local planning dept...)

That joint can be sealed 'properly' using something like Stixall; the fitting would need pulling apart and the insert coated with a suitable sealant before refitting. What's been done is only a poorly-applied smear on the outside of the join by the looks of it. 

This is really helpful - it will be useful when the roofer comes back if he doesn't have any better ideas.

Jeepers_Creepers

I've just re-read your first post; "The upstairs neighbours have renewed a downpipe which takes rainwater and grey waste water from their two bathrooms."

This pipe is handling the waste water from two bathrooms? So presumably these bathrooms also have toilets in them? In which case they must surely also have soil pipes - 4" jobbies coming vertically down the wall? In which case, why isn't the waste water  going into this pipe as it should?

Having that downpipe reserved solely for rainwater wouldn't stop it from leaking due to its crazy low angle, but at least it would be clean water...

Is the house old? Do you know if it has a 'soakaway' to handle the water from the rainwater downpipes? It's been the case for a good number of years (no idea how long) that foul/waste/grey water goes into the sewers, but all rain and surface water goes to a soakaway. This is controlled by building regs. I think it's highly likely that the current setup breaches regs, even if it's down to the choice of pipe used. 

starving_artist

Jeepers_Creepers said:

I've just re-read your first post; "The upstairs neighbours have renewed a downpipe which takes rainwater and grey waste water from their two bathrooms."

This pipe is handling the waste water from two bathrooms? So presumably these bathrooms also have toilets in them? In which case they must surely also have soil pipes - 4" jobbies coming vertically down the wall? In which case, why isn't the waste water  going into this pipe as it should?

Having that downpipe reserved solely for rainwater wouldn't stop it from leaking due to its crazy low angle, but at least it would be clean water...

Is the house old? Do you know if it has a 'soakaway' to handle the water from the rainwater downpipes? It's been the case for a good number of years (no idea how long) that foul/waste/grey water goes into the sewers, but all rain and surface water goes to a soakaway. This is controlled by building regs. I think it's highly likely that the current setup breaches regs, even if it's down to the choice of pipe used. 

It is an old house and the conversion was done probably 40 years ago so I think it predates building regs.  There is a soil pipe so not sure why the grey water wasn't routed in to that.  May be the rainwater pipe was closer.   Believe it or not the fall on the pipe was actually increased when the new one was installed. There is no soakaway it all goes in to the sewer.

Jeepers_Creepers

It doesn't make sense that the rainwater downpipe we can see waaaay in the far corner of the house is closer than the soil pipe which must be coming out of the same bathroom! Can you see this soil pipe on the outside wall where their bathroom is? If so, where do the waste pipes come out through that wall in relation to it?

Summat's weird. 

starving_artist

Thanks for sticking with this Jeepers.  It's been hard to find anyone with any thoughts on this even though I see plenty of complicated drain arrangements on the sides of buildings so I can't believe it is that unusual.  I've added some more pictures so you can see the whole arrangement:  https://postimg.cc/gallery/rzLj7Z9  Some of them show the route of the previous rainwater downpipe which was even shallower but the general arrangement is the same.  I also need to correct what I said before - only the waste water from the upper bathroom connects in to the downpipe.  They were going to connect the lower bathroom waste water but ended up connecting it in to the soil pipe which also takes their kitchen waste water and two toilets.  That soil pipe goes directly down through my flat roof and connects internally to the sewer below the house.  The far downpipe at the very rear corner descends to a ground level gully connecting to a manhole close by.