Svp Re-route

[Ed12345]

Hi I’m building a single story flat roof extension on the side of my house and looking for alternatives to having the vent pipe boxed in extension and passing through new roof, lower pipe which is a shower is about 60mm above ceiling height of new extension the 4” is a toilet, major job to do anything internally so was wondering if I could take shower through roof space of new build and toilet above and put them into a new pipe on outside building, the first pic shows pipes with ceiling height marked and second pic what I’m proposing any help greatly appreciated

 

[^woody^]

Yes above if you have the angle to the SVP.

You'll need a trimmer if fitting within the roof structure.

 

[Ed12345]

Thanks for replying woody will be tight but think I can just get enough fall to make it work