Connecting into existing soil pipe

[Frankofthenorth]

Hi,
I want to install an ensuite within my attic bedroom. The current soil pipe is shared with the neighbour on the left. My property is to the right of the ginnel. I am aware that the existing soil pipe is probably not fully compliant with regs as it has an offset in and the connections into it are less than 750mm from the offset (mine just below coming from the branch pipe and neighbours straight in above the s bend. There have never been any issues in the many years I've lived here.

My question is whether I would be able to connect a higher level soil branch pipe for a WC near to the top of the stack which is currently just serving the AAV. (I would also raise the stack height and AAV to be above the inlet level). This would elbow out of the property just below the gutter level. Would there be any issues with the height of the drop with waste water/solids hitting the 45 degree offset and then the S bend? Do you think BC will accept this as the pipe is already in place?

Without installing a new soil pipe the only other options I can think of are: install a mascerator so only liquids are discharged into the new inlet at high level, or run the new soil waste vertically down the wall and join into the existing branch pipe?

Thanks

 

[Hugh Jaleak]

Bigs of a pigs ear of pipework, but given the worst bit is on the Neighbours side, you are limited as to what you can do with it.

I think in all honesty, I would drop a new pipe on your side of the Boundary, and connect into the branch at a suitable point. Any issues with noise when falling waste hits the bottom will be on your side, going in higher could possibly risk making a racket int he Neighbours bathroom when discharges hit the bend, immediately under their WC connection.

Take the pipe up above the eaves, and terminate in an open vent if possible.

 

[Frankofthenorth]

Thanks, do you mean something like this @

Bigs of a pigs ear of pipework, but given the worst bit is on the Neighbours side, you are limited as to what you can do with it.

I think in all honesty, I would drop a new pipe on your side of the Boundary, and connect into the branch at a suitable point. Any issues with noise when falling waste hits the bottom will be on your side, going in higher could possibly risk making a racket int he Neighbours bathroom when discharges hit the bend, immediately under their WC connection.

Take the pipe up above the eaves, and terminate in an open vent if possible.

Thanks, do you mean something like this @Hugh Jaleak . Is it acceptable to regs to install a section of vertical stack that isn't the soil stack itself?

 

[Hugh Jaleak]

Thanks, do you mean something like this

Yes.

Is it acceptable to regs to install a section of vertical stack that isn't the soil stack itself?

Yes.

 

[Frankofthenorth]

I've spoken to a plumber who isn't convinced this is to regs - reading the approved doc it isn't mentioned specially, anyone got any thoughts which part of the regs covers this?

 

[Hugh Jaleak]

I fail to see an issue, whilst it's not conventional, you're adding to an existing installation, and have to work around what's already there. Regs simply state 'Bends are best avoided in the wet section of a stack', but there are occasions when they are unavoidable. Nothing you've suggested in your illustration gives me cause for concern.

The Dry (vent) section can be run more or less as you please, provided it doesn't have any dips where water could collect, thus blocking the free passage of air through the stack.