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Discuss Relocating kitchen sink in the Fittings & Pipes area at

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  1. Rach1984

    Rach1984 New Member

    Hi all,

    I'm looking to relocate my kitchen sink to a new location that will involve digging a trench through the length of the kitchen and laying pipes in the concrete floor. So far I've had inconsistent advice from our plumber, our builder (who took advice from a plumber he knew), and the building control team at our local council.

    The distance between our proposed sink location to the soil stack is 4m, and we plan to get there in a straight run with no bends. My query has three parts:

    What pipe size do I need? (It will be servicing a sink and dishwasher)?
    What fall do I need over the 4m run?
    How much concrete cover is required?

    Any help or guidance will be appreciated. Thanks in advance for your help.

    Rach :)
  2. JCplumb

    JCplumb Plumber

    The rule of thumb for fall is 1 in 80, so about 5cm over 4m.
    No matter how careful you are you will get grease/fat down that pipe so make sure there's a rodding point at each end. I'd put one in the middle too if practical although that may be overkill.
    As for pipe size, I think 50mm is required for a 4m run, although I don't know the regs off the top of my head, I normally look it up in my 15 year old Treloar book if I need to know for sure, or google it :)
  3. Rach1984

    Rach1984 New Member

    Thanks JCPlumb,

    We've been told by our plumber that a 4" pipe will be needed as it's underground and will be stronger and also less prone to blocking. Our builder thought 2" was sufficient though, and he confirmed this with a plumber he'd worked with in the past. I have since gone back and queried it with our plumber who has confirmed with a colleague that a 4" pipe is definitely needed. I'm really just in the middle trying to make a judgement call based on the advice I've had so far. I'd be interested if anyone else had a view...?

    With regards to the access point, would one in the middle of the run be sufficient rather than one at each end? There will be a kitchen island in the middle of the run so we could conceal an access point underneath.

    Thanks again JCPlumb, your reply was appreciated.

  4. JCplumb

    JCplumb Plumber

    What did the building control team say?
    They know their onions.
  5. Rach1984

    Rach1984 New Member

    They're on my to do list for tomorrow, although I've already had some contradictory advice from them on a separate issue. The annoying thing is everyone is being really helpful, it's just nobody seems to agree with each other.

    I'll let you know what they say after I've spoken to them, but in the meantime if anyone else has a view I'd really like to hear it. So far a 2" pipe has three votes and the 4" pipe two!! :)
  6. PhoenixServices

    PhoenixServices Plumber GSR

    Me personally a 4" pipe, just because kitchen sinks get all sorts of chucked down them. Lot cheaper to go a bit overkill now than redo later or have the hassle of keep unblocking.
    • Like Like x 2
  7. Dan Brown

    Dan Brown New Member

    Aswell as JCplump giving very good information to Rach, he/she has also given me some good information too. Thanks for the good info JC :)
    • Like Like x 1
  8. JCplumb

    JCplumb Plumber

    You're welcome, but how do you know I'm plump? :D
  9. Dan Brown

    Dan Brown New Member

    I do not know that you are plump, i just know that you gave me some great info, your name is also JCplump. :D
    • Like Like x 1
  10. Molesey99

    Molesey99 New Member

    Hi, would you mind sharing what Building Control requested regarding pipe thickness? I'm in the same boat at present. thanks a lot
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