Soil pipe relocation - where to locate vent?

[Tetrarch]

I'd like to relocate a toilet. I intend to run the soil straight out through the wall and then run the pipe about 2m horizontally (with fall) along the wall before cutting through a flat roof (above the downstairs toilet) and then joining to the soil just above floor level.

Where should/can I locate the vent?

Directly above the exit from the wall or directly above the roof penetration? The joint for the former would be a fairly complex x,y,z axis arrangement, whereas the latter would be a simple branch

Regards

Tet

 

[Hugh Jaleak]

Vent can go above the junction, where the horizontal branch enters the vertical stack, provided it is sufficient distance from any opening into the property.