Soil stack

Good morning I am seeking a bit of advice in regard to the soil stack I will need in my new extension. My architect has the pipe running between my new upstairs family bathroom & en-suite bedroom. It then runs internally down through the kitchen where it will exit and then eventually join my current system and on to my septic tank.

The outside requirements are obvious but what he has not put on the drawing is if it terminates through the roof or not ?

If it is a normal SVP then it would have to exit the roof between the roof light and the dorma bathroom. How high would this be or could I use a durgo valve and terminate in the en-suite ?

i would use a durgo not sure on regs but im sure open vent has to be above highest window dont think thats a reg just common sence hope thats helped just a thought do you really have to go through the house ??

Its thr front of the house and I guess if it ran through it would get in the way of the porch.

If it's within 3m of a window it needs to terminate 0.9m above the top of the window. You could use a tile vent if there's space in the roof void to connect it

If it goes to a septic tank, I'd vent it. Septic tanks can get excited sometimes, have seen the result when one 'burps', and it wasn't pretty.