Where would you run sewage pipe to a toilet in the loft?

[405 TD Estate]

I guess if the pipe were to come out of the back of the house where the pipe for the normal loo comes out it would have to come through the tiles in the roof - is this just a bad idea?

[Owain]

I would think so.

You might be better dropping the pipe into the room below and boxing it in at a wall/ceiling corner.

Owain