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Pouring a concrete floor over c/water supply pipes

Discussion in 'Plumbing and Central Heating' started by Bob99876, 5 Jul 2021.

  1. Bob99876

    Bob99876

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    Hi, I've had a supply pipe leak repaired and am now in the process of digging out and replacing the sub-floor. Unsure of what I do with the pipes though.

    Can I do preparation, sleeve the pipes and then just pour concrete over?
    Do I need ducting, if so which type and how do I fit it round a connected pipe?
    Do I need to keep those joints accessible, how?

    This is on a shared supply, so turning the water on and off is not easy to do. I had a leak, which was covered under insurance, but reinstatement of the floor wasn't. I'm just wondering where I go from here.
     
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  3. dilalio

    dilalio

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    That's unusual, insurance claims for such events normally cover everything EXCEPT the repair of the pipe! It's been that way for every insurance job I've worked on.

    As for the pipe repair (renewal), I would suggest that the lead supply be got rid of completely if practically possible and have it rerun in mdpe all the way to the stopcock.
    Lead main not good, inaccessible joints not advisable and inaccessible "compression" joints a real no-no!
    Aside from not being good for supplying potable water, that lead main is likely to continue to fail along the rest of its length due to age and you're back to square one.
     
  4. dilalio

    dilalio

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    Double check your insurance for trace and access. I'd be going back to them on this one!
     
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  5. Bob99876

    Bob99876

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    I have, they cover trace and access, but not reinstatement. The leak was on separate insurance.

    To be fair, I'm guessing they'd only reinstate to the same standard if I was covered. I want to take up those bricks (I've removed most) and loose rubble and put in scalpings, DPM, sand, and then concrete. Just unsure what to do with the pipes.

    House was built in 1851.
     
    Last edited: 5 Jul 2021
  6. Harry Bloomfield

    Harry Bloomfield

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    If the pipe is in contact with the concrete, the cement will attack the copper and cause leaks - it needs to be isolated from it.
     
  7. Bob99876

    Bob99876

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    It's solid floors throughout, and the new supply would come from the front of the house rather than the back. That would mean taking it upstairs from the living room (and digging a hole in it), carpets up, through the floorboards and then dropping down - that's if I can get it past the joists. I'm assuming this is why noone else on the street has had it done.

    I'm tempted to try and dig the lead out but it's a fair depth and I'm not sure precisely where it runs and it looks to be pretty deep.

    Can I put inspection chambers in for the compression fittings?
     
  8. dilalio

    dilalio

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    Hmmn... Just done a bit of googling and found this (see link).

    According to the study, tests have shown that OPC (ordinary portland cement) mixed with sand to make concrete, does not corrode copper. Only when some additives are included, can there be a risk of corrosion.

    Most of the risk is from abrasion due to lateral expansion where copper enter/exists concrete and, could also cause buried joints to pull apart, one could assume.

    Protective tape such as Denzo is something we've always used, or felt lagging with a combined plastic sleeve.

    New one on me this.

    https://www.copper.org/applications/plumbing/techcorner/problem_embedding_copper_concrete.html
     
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