IMM wrote:
You cannot run the stack around the bathroom.
Paul, you can run the branch pipe to the stack around the bathroom.

It requires a minimum "fall".
You require a minimum fall, over 10' with a 90deg this will be around 3"
The 'approved' minimum is 9mm per m, up to a 6m straight run to the stack.

You will probably have to dig up outside and extend the stack
underground to the correctly position.
You won't have to dig up outside or extend the drain to meet the invert of a
new stack as suggested above.

A branch discharge pipe should be fully accessible for clearing blockages,
hence the preference for external pipework over boxed-in internal pipes. A
bend in a branch should have as large a radius as possible.

and then rise up to the toilet position.
A long vertical drop (1.5m) from a wc should be avoided to prevent
self-siphonage of the trap.

--
Toby.

'One day son, all this will be finished'