Add toilet upstairs

[Cally D]

hi I've just bought a house with the only toilet downstairs and just bathroom upstairs. Both are located at the front of the property but the soil pipe is at the rear of the property. I want to add a toilet upstairs in the bathroom and wanted to know if it's possible to have waste going into soil pipe for toilet downstairs which is directly below. I've drawn a diagram hope it makes sense. Many thanks

 

[Newboy]

In principle quite straightforward - may need a bit of juggling depending on which way the joists run. Taking it outside the building and back in is a no though. Just a vertical internal stack will do.

 

[Cally D]

Thanks for your reply much appreciated. What are the complications with running pipe out then back in? It's just to add things to it my combo boiler is directly below which is why I was hoping for the external option. Internal is possible but my concern was having more 90 degree angles. Cheers