I am considering a new layout for a flat, I am wanting to locate the Kitchen and bathroom a long way from where the soil pipe exits the building. (its an upper floor flat with concrete floors) The kichen sink will be the furthest away (30' from the down pipe) with the toilet being some 16' from the down pipe. The kitchen waste will need to flow into the soil pipe at the back of the toilet.
If the back of the toilet is 5" above the floor and 190" from the outside downpipe this will give me a 1:40 gradient, will this be acceptable using a
4" pipe to carry all kitchen toilet and shower waste?Just thought the shower cubicle will need to be raised, I suppose an 8" step into the shower won't be too odd!