Would the above work? I have an existing long run (about 4m) from the shower drain to soil stack (includes a ptrap and venting). But I want to run the initial waste under the floor boards so I don't have a box running down one side of a wall. Would the proposed drain be suitable in your opinion?
Couple of notes:
1) Drain pipe is currently 40mm diameter
2) The riser where the pipe comes through the floor again in my proposed solution would be accessible (and hidden) - will likely have a screwed top for access.
3) The drop is about 1 in 40.
Appreciate feedback and comments from more experienced plumbers and DIY members please.