KITCHEN WASTE 40mm DIRECT TO UNDERGROUND DRAIN INSIDE KITCHEN?

[martcrox]

A new kitchen extension has an extension to underground drain running through it which will terminate in a new outside gulley. Is it OK to take a branch off this before it passes through foundation into garden for gulley so I can have a low stump under kitchen units to attach a 40mm waste adaptor?
My builder doesn't think so but I showed him FloPlast schematics that show virtually the same thing. The 40mm adaptor would have typical u or p trap at sink or dishwasher. I can't see the difference between this & connecting directly to a soil stack outside as it's still linked to drains & your relying on water seal for blocking drain smells.

 

[stevetheplumber]

A new kitchen extension has an extension to underground drain running through it which will terminate in a new outside gulley. Is it OK to take a branch off this before it passes through foundation into garden for gulley so I can have a low stump under kitchen units to attach a 40mm waste adaptor?
My builder doesn't think so but I showed him FloPlast schematics that show virtually the same thing. The 40mm adaptor would have typical u or p trap at sink or dishwasher. I can't see the difference between this & connecting directly to a soil stack outside as it's still linked to drains & your relying on water seal for blocking drain smells.

yes you can go direct to drain make sure you put a cleaning eye on to make it roddable

 

[justlead1]

Hi It was seen as good practice to fit waste into a back inlet gully. Good Luck

 

[martcrox]

Thanks to everyone for help & reassurance. All in & passed by building control. 45 deg T branch leading to rest bend & 18" riser with 40mm adapter on top for floor level connection behind base unit. All roddable.