Wow I'm really not having a good day with technology! Just lost another beautifully crafted post.
Thankfor your responses. Essentially it's a lead vertical stack pipe in a victorian building. Ground floor = cafe. First floor = our flat. Three floors above = one large HMO property with which we share common entrance/staircase. The stack pipe is in the party
wall next to the staircase, with a full-height access panel. Problem is there is essentially no drainage at the principal level of our flat - the bathroom is actually outside our flat on the next landing up, where the stairs return. The toilet, sink, shower, etc, feed in here. Below this is a sort of under-stairs cupboard accessed from within our flat, containing a small sink that represents the extent of the kitchen (!) and then beyond that there is a bulkhead that goes over the staircase below as it comes up from ground floor level. So the sink drains over this thigh-high bulkhead.
Still with me?! We need to put a proper bathroom and kitchen inside the flat, which means drainage at a lower point than the lowest existing joint to that stack. Even if we can use a macerator and pump to get toilet waste up and over the bulkhead and utilise that existing sink drainage with a smaller pipe, there will also be kitchen waste coming in from the front room of the flat (essentially further along the same party wall as the stack pipe, so we can chase along the wall beside the stairs and in that way).
I've done some reading up on here and it seems like my options are either to wipe in a piece of copper then connect the plastic on to that, or use some sort of rubber/finned connector. However I spoke to Fernco/Flexseal today and they said they do not recommend the use of their products.
Am I on the right lines? Is it even possible to cut into a vertical pipe low down like this without compromising its structural viability? Builders are telling me they can't quote for the work until they know the extent of the plumbing work involved. So here I am, getting a quick education on the subject! Any advice would be gratefully received!
Anna