No.1 U.K. Professional Trade Forum, Plumbing, Gas, Electric, Tiling and Joinery Forum

Hi new to the forum , doing an extension to the rear and side of my property , couple of questions regarding drainage etc , first of all I need to move my soil stack about 6 ft to the right of its location , under manhole shows a different pipe which goes under house to downstairs toilet I was thinking of cutting pipe and adding a Y joiner piece and teeing off that for new stack location then getting rid of existing pipe etc if that makes sense I’ll add photo for my idea thanks rob

I cant see the photo so cant see what your intention is, but if your building an extension, your building control officer will be able to tell you how he/she wants the drainage doing. My understanding was that all drains should lead independently back to the manhole so they are rodable in the event of a blockage. Due to this your plan of using a y joiner will not be allowed and instead a mini access chamber will likely be the preferred method for the connection.

The problems you will have to just tee off where you suggest is although it will work, you then will have a junction that has no access to.
Also building control will not approve it, but you should really be contacting them first.
Ideally you require a new man hole either to replace existing in your photo, or dig and install a new man hole where new sewer pipe connection goes at existing pipe further on

First thing is to get building control involved and ask what they want to see.