We have applied planning permission for a kitchen extension which doesn't appear to be a problem but we have run into a possible problem with the neighbour over a stench pipe (is this called a soil stack these days?) Anyway, we don't appear to have one, but she does which she believes is shared. From what I can gather she doesn't want it to be shared any more. I don't know if this is a problem or not. I have several questions: 1. Why don't we already have a stench pipe? 2. Is it unusual for older properties to share one? 3. Is is possible to have our own and terminate the sharing without it costing the earth? It appears from some old plans I have come across that our drainage does go on to her land to join the mains. I don't know if this is relevant.