Building inspector issues with kitchen draining

Discussion in 'Builders' Talk' started by Dilby, Sep 15, 2020 at 1:14 PM.

  1. Dilby

    Dilby Member

    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!
    Last edited: Sep 15, 2020 at 1:25 PM
  2. Hans_25

    Hans_25 Screwfix Select

    I'd start by clarifying what was asked of the builder - what was supplied? Drawings? Spec? What did the builder quote against?
  3. Dilby

    Dilby Member

    Thanks @Hans_25 - Probably guilty of info overload there. I need to go through but for now does that sound right to you; that you're not allowed to run 32mm waste pipe in the concrete?
    Abrickie likes this.
  4. spannerw

    spannerw Active Member

    In your first post you don't mention 32mm waste pipe. Confused????
  5. nigel willson

    nigel willson Screwfix Select

    You did say 40 . But either I would run in concrete. Very likely to block especially from a kitchen
  6. Dilby

    Dilby Member

    Sorry, I mean 40, not 32. Ok interesting Nigel thanks - I guess my argument is that is what's been there for over a decade with no issue, and if it did block then you easily have access from the wall to rod it. I'm going to guess that's not good enough for a building inspector though.
  7. Hans_25

    Hans_25 Screwfix Select

    If the BI has said you can't run 40mm then you can't run it, at least he won't sign it off which amounts to the same thing.

    Personally I wouldn't do it unless the distance was short and there was a decent fall on it.
  8. Dilby

    Dilby Member

    I can't get a hold of the building inspector at the moment and wasn't here when he came, it's what the builders have told me and they are waiting for my go ahead to do that extra work. So I'm just trying to find out if that sounds right or if people wrote back something like 'no way, you can run that, we do it all the time' etc.
  9. Hans_25

    Hans_25 Screwfix Select

    Easier to do it right now than try to rectify later on.

    I'd get the 110mm laid now and sort out the finances later. Did the builder charge you for laying the 40mm pipe? He should only charge you once, if at all.
  10. Dilby

    Dilby Member

    Thanks for the reply, appreciate it. He forutnately hasn't laid that 40mm pipe yet, he'd just added the gully for it to run to. But the inspector is apparently saying we need to have that gully anyway as a 'rodding point' even though there's nothing else going to it and it's only 1 foot from the chamber. The extra work will be digging channel, and running the new pipe through the existing base of the wall which will need to have a lintel added.
  11. Dilby

    Dilby Member

    Also another question is can I run my own pipe outside of the wall at a later date - at what point would that need to be a part of a building inspection or defy building regs? Thanks
  12. nigel willson

    nigel willson Screwfix Select

    Depends what the purpose of said pipe is.
  13. metrokitchens

    metrokitchens Screwfix Select

    Run 110mm soil pipe to suitable point outside of house and fit a drain. Run 40mm waste inside kitchen as appropriate, core 40mm waste through wall, run waste outside as required and drop down into drain.

    fairly standard method. No 110mm core below ground and no lintel, no breaking up floor inside.
  14. Frutbunn

    Frutbunn Active Member

    Technically no as it is work that requires B regs, but I'm assuming you mean that you intend to do it after having the B reg completion in which case they are unlikely to know about it.
  15. Dilby

    Dilby Member

    Thanks - the main problem here that I didn't mention is the sink is on an island so requires the pipe to be sunk. Here lies the problem ; builder wanted to use 40mm waste pipe to gully as you mentioned (which he'd already setup with 110) but builder thinks 40mm is too narrow to be sunk, even though you'd have access to any blockages where it came out to the gully.
  16. rogerk101

    rogerk101 Screwfix Select

    Why not use 50mm waste pipe from the island?
  17. Dilby

    Dilby Member

    Thanks for reply. This was the plan but because its from an island it would need to be buried as no cabinets to hide it, and the inspector has said nothing below 75mm can be buried.
  18. koolpc

    koolpc Screwfix Select

    You think a builder would be clued up on these matters!
  19. Rob_bv

    Rob_bv Active Member

    Speak to the inspector direct; there may be some miscommunication, or the inspector may be under the impression that it is tying into the gully below ground. Whenever I've done extensions previously, inspectors insisted on a minimum buried size of 50mm (but that may have changed).
  20. Dilby

    Dilby Member

    Thanks Rob and everyone else. Yes I managed to get hold of the building inspector; he confirmed min of 75mm can be buried, stating the reason is access if it gets blocked. I then asked what if it comes out of wall into a gully where you have access to unblock and he said yes you can unblock it but it needs to buried. Then I'd ask why it needs to be buried and he's say in case it gets blocked and you can see the loop we got into. In the end he was just getting annoyed so I figured it's best to just do what he wants rather than **** him off. But at least I've been able to clear up the situation and know we 'needed' to do it. The weirdest thing though is he's asked us to keep a gully, even though there's nothing running to it. Guess it was just hte side of the bed he woke up on!

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