I have a n older property where the WC from the bathroom has its own connection direct to the drain ( underground gulley with a manhole cover on it) and the bathroom basin and bath itself empty into a ground level open gulley. It all works okay. the thing is the open gulley is right next to the back door - I was wondering if I can just convert the top of the gulley into a stack arranegment. There is a trap below the open gulley already. I was wondering if its possible to just take the top if the gulley away and fit a short stack and join the batha nd sink waste into it with an vent on top... Bearing mind it has a trap below ground - would I need to go above window level or not.. Any guidance gratefully recieved...!
