I am trying to plan the stub stack for our downstairs toilet. The 110mm pipe is set in the slab and goes direct to a manhole outside. The cloakroom has a toilet and sink only.
The stub Stack will be in the corner of the room.
Does it have to be 110mm with a 110mm AAV or can i use say 50mm for the stack only with a 50mm AAV, allowing the stack to be hidden