Hi all - I've got a builder here doing a kitchen extension and I was hoping someone could help me understand an 'point of contention' that's occurred. Despite going over it with him several times, our builder denies it was in his remit to worry about draining from the kitchen (sink/dishwasher) and so didn't have a feed for it to the existing chamber. So after I asked him about it, he suggested we lay 40mm pipe in the slab (not sure if at time of pouring or by chasing it in afterwards) and then run it out the side of the house and into a gully via an elbow joint. I agreed and so he added the gully to the chamber and had the building inspector around. But the building inspector has said you can't do that as 40mm pipe gets blocked (even though that's exactly what is there now and not an issue, plus you'd be able to access it easily from outside and clean it), and now we have to dig it all up again and have a new soil pipe running to the chamber from where the new sink will be, but we have to keep the gully as a rodding point, even though I assumed a manhole would be a rodding point in itself. The builder has told me I can either foot the bill for the extra work or okay using the 40mm pipe and I'd still get building regs, but it means that I'd have to come back to the council on that particular part of the build. I'm not sure how true that is, and what that means if I ever had to sell the house. I'm not a builder (semi-confident DIYer but that's it) so i'm caught between lingo and parties and would appreciate some helpful advice/thoughts. Many thanks!