Soil Pipe in roof space

[canflush]

Can an expert tell me if I can locate the soil pipe from the upstairs toilet across the exterior wall whilst inside a roof space, being the single storey kitchen, obviously connecting to the main soil pipe at the side of the extension. Hope this makes sense?

 

[stevetheplumber]

Can an expert tell me if I can locate the soil pipe from the upstairs toilet across the exterior wall whilst inside a roof space, being the single storey kitchen, obviously connecting to the main soil pipe at the side of the extension. Hope this makes sense?

from your description id say yes provided you can keep the fall