leaking downpipe repaired with mastic tape

Jeepers_Creepers

Image 474 is the most helpful here, although I'd like to see it further down too to see what happens.

That image shows the 4" soil waste pipe running down the corner of that wall, and this has the toilet waste going in to it just above that window arch?

To the left of that window arch is normal 2" downpipe for the rainwater, but it's had a hopper added presumably so that the basin/shower waste waster from that bathroom can also decant into it? If so, I'm guessing the reason they did this was to avoid that waste pipe going across over the window to get - as it should - into the 4" pipe. Ok, these pipes are ugly, but would having that 1.5" pipe cutting across possibly just the red brick arch really be a sin? 

I don't know what to suggest. As I understand it, it's 'wrong' - breaks Building Regs - but just how serious it is I cannot comment. Certainly I'd complain about having 'grey' water coming on to my roof...

theoretica

Not a definite, but my thought is a roofer may be used to dealing with gutters - but not grey water.  So applying wrong set of practical knowledge and your upstairs neighbour employed the wrong craftsman and needs a plumber.  But I would expect a good workman to say when a job moved out of their expertise area.

starving_artist

Jeepers_Creepers said:

Image 474 is the most helpful here, although I'd like to see it further down too to see what happens.

That image shows the 4" soil waste pipe running down the corner of that wall, and this has the toilet waste going in to it just above that window arch?

To the left of that window arch is normal 2" downpipe for the rainwater, but it's had a hopper added presumably so that the basin/shower waste waster from that bathroom can also decant into it? If so, I'm guessing the reason they did this was to avoid that waste pipe going across over the window to get - as it should - into the 4" pipe. Ok, these pipes are ugly, but would having that 1.5" pipe cutting across possibly just the red brick arch really be a sin? 

I don't know what to suggest. As I understand it, it's 'wrong' - breaks Building Regs - but just how serious it is I cannot comment. Certainly I'd complain about having 'grey' water coming on to my roof...

You are spot on reading that photo.

This one shows what happens further down with the soil pipe entering internally via the flat roof

and the downpipe veering off round the chimney breast.  They ended up making the connection for the waste water from the lower bathroom from the bottom of the chimney breast and running it just above the flashing and in to the soil pipe.  As you say, far from ideal.

 

Jeepers_Creepers

I can't get my head around this at all.

I can't see any reason why the rainwater and grey water cannot be separated. The former would need to either continue around the wall until it gets to where it currently goes, or else a suitable trap would need installing in the ground to accept it, in a direct line down from where it is (it would ultimately end up in the sewer, joined in with that 4" soil vent pipe).

The grey water could just continue down - separate from the rainwater - until it bends across to that soil pipe and connects to it via a boss.  This could be done at any height, even just above ground level - allowing for the required gradient (that grey fitting at the bottom already has a collar ready to take a pipe!) 

What they've done probably saves a bit of bother, but there are proper solutions available. If that 4" soil pipe had not been there, then I can imagine a lazy builder trying to run ridiculous pipe routes to a distant corner as the 'proper' way would have been to install an underground soil pipe going to that area. However, they already have this in place. 

Weird. 

starving_artist

Jeepers_Creepers said:

I can't get my head around this at all.

I can't see any reason why the rainwater and grey water cannot be separated. The former would need to either continue around the wall until it gets to where it currently goes, or else a suitable trap would need installing in the ground to accept it, in a direct line down from where it is (it would ultimately end up in the sewer, joined in with that 4" soil vent pipe).

The grey water could just continue down - separate from the rainwater - until it bends across to that soil pipe and connects to it via a boss.  This could be done at any height, even just above ground level - allowing for the required gradient (that grey fitting at the bottom already has a collar ready to take a pipe!) 

What they've done probably saves a bit of bother, but there are proper solutions available. If that 4" soil pipe had not been there, then I can imagine a lazy builder trying to run ridiculous pipe routes to a distant corner as the 'proper' way would have been to install an underground soil pipe going to that area. However, they already have this in place. 

Weird. 

I agree it's not well arranged.  As I mentioned they have now connected the lower bathroom's grey water in to that fitting you pointed out on the soil pipe (the photo above was before they did that).  BTW that is my flat roof at the bottom of the picture not ground level.

They are not going to separate the top bathroom's grey water from the rainwater now though so seems like the only solution is what you suggested earlier pull the connection apart where the leak is and apply a sealant.

Jeepers_Creepers

Ah, I thought that was the ground. Doesn't make much difference, tho' - it would be easy to send the 'grey' into that 4" vent pipe. 

Although 'wrong', I guess it isn't a major issue - unless leaves block that crazy low sloping downpipe, and you end up getting your neighb's lovely soap suds frothing over your roof. 

If it goes wrong in the future, I think you'd have a legitimate case of insisting they send the grey into that vent pipe. 

starving_artist

Jeepers_Creepers said:

Ah, I thought that was the ground. Doesn't make much difference, tho' - it would be easy to send the 'grey' into that 4" vent pipe. 

Although 'wrong', I guess it isn't a major issue - unless leaves block that crazy low sloping downpipe, and you end up getting your neighb's lovely soap suds frothing over your roof. 

If it goes wrong in the future, I think you'd have a legitimate case of insisting they send the grey into that vent pipe. 

Thanks Jeepers. Appreciate your help on this.