68mm rainwater to 110mm Soil

[SteveBoy]

I am currently looking at the possibility of adding a downstairs toilet and basin and the only viable drain is a 68mm rainwater on the outside of the wall where the cloakroom will be. I have combined drains at my property, the 110mm drain is reduced down to 68mm CI and runs as a rainwater to the gutter above which is about 3m high. What is the best way to add in the pan and basin waste? Can I upgrade the current 68mm and run it as 110mm soil right up the wall and vent above the gutter and if so what is the best way to accommodate the current gutter outlet. Please see the picture attached for more info. Any information would be greatly appreciated, thanks.

 

[Murdoch]

If its draining into a surface water system you can't connect a dirty water soil pipe to it.

 

[king of pipes]

Forget the 68mm that is solely for rainwater if theres suitable drainage under ground then this would need excavating and a branch cutting into the underground pipe a new soil stack would be connected to the branch to accept the toilet waste ect . Kop