I am about to install a small en suite toilet to the top floor of a mid
victorian terrace house 2up 2 down type. At present the bathroom and toilet
are in a small extension on the ground floor.
I intend to run the waste pipe through the wall accross the back of the
house at an angle over the roof of the extension and then join on to the
waste stack at the back.
Question is do I have to have some sort of vent where the pipe first exits
the back wall or will it run down as described without a problem.