Pipes in concrete floor

Discussion in 'Plumbing and Central Heating' started by chriselevate, 7 Jun 2018.

  1. chriselevate

    chriselevate

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    The house I’m in is 1970’s built and I looks like the central heating system ground floor is run in the concrete of the floor. All floor coverings are up at the moment and I can’t decide if it’s something (yet another thing on the huge list) that I should sort out whilst I have the opportunity.

    There are soldered fittings (I guess not ideal as these are potentials for leaks) and I can see that the hessian lagging used has perished away.

    I guess cooper pipes buried in concrete is it ideal for lots of reason but I’m wondering what advice you guys have now I’ve found some of them.

    Thanks
     
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  3. Steve

    Steve

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    I bought a 1950s house two years ago. When the floor covering was removed, it was revealed the central heating pipes were in concrete in several locations. And a gas pipe. When they were removed all were badly corroded. There was a mild smell of gas, suspect it was leaking under the concrete. Either that or the lead gas pipes that were still in use elsewhere!

    I repositioned all the rads for the new system and where necessary ran the pipework behind the new skirting. Nothing in the concrete.
     
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  4. chriselevate

    chriselevate

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    Yeah ideally I don’t want the pipes back in the concrete but it looks like there little option here.

    Some people swear by denso take, others gaffa and then hessian lagging and others conduit/wrapping in pipe. Difficult to know what is best.

    Anyone got any advice on this please?

    Thanks
     
  5. Combicert

    Combicert

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    Well i guess you have 3 options.

    In the floor

    Buried in a wall

    Surface mounted


    ——


    You dont want floor

    You probably don’t want surface mounted...
     
  6. chriselevate

    chriselevate

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    I think buried in the floor is the only option to be honest. Not ideal but if protected correctly (how would you protect them) they will be fine unless a fitting lets go etc won't they?
     
  7. Combicert

    Combicert

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    You could always feed them throught a bigger pipe if you werent convinced. Denso tape.
    Old fella i worked with would use carpet tape (!)

    Personally... rightly or wrongly ... i’d feed them through some flexi pipe if it was a short run and i had some to hand. Failing that - denso tape.
     
  8. Combicert

    Combicert

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    You could always try to run the pipe in an easily accessible place - aso that if the worst was to happen you dont have to rip out kitchen units etc.

    Are you tiling over it..? Laminate..?.

    Also, these are all water pipes, yes..? No gas..?
     
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  10. chriselevate

    chriselevate

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    The go right across the middle of the kitchen.
    I have CH pipes with a Gas pipe on top.
    It's going to have Karndean (or similar) fitted on top.
     
  11. Combicert

    Combicert

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    Gas pipe must have at least 25mm screed cover.

    It must be protected either with:

    A) factory sheathed pipe
    B) pvc wrapping or bituminous painting (wrap with 50% overlap)
    C) or can be tracpipe
    D) copper in a pre formed duct

    No compression joints or unions may be buried

    Must be tightness tested before it’s buried/reburied

    Gas safe register has offered further guidance in a technical bulletin. When i get chance i’ll look it up.


    Bottom line. Don’t touch the gas mate - get someone in who’ll stick their name on a bit of paper to say it’s safe. Don’t just replace a bit of copper pipe and slap screed on top.
     
  12. Gasguru

    Gasguru

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    I've always covered the pipe in hessian lagging (but not the version you wrap around), then wrap 50mm pvc tape with a 50% overlap. Protection and plenty of pipe expansion allowance.
     
  13. Keithmac

    Keithmac

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    We have a house with concrete floors, the CH is run in the ceiling and drops down in the corner of the room, boxed in.

    Same with water feed.
     
  14. chriselevate

    chriselevate

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    Ok, so a gas safe plumber has been round to assess the pipe work I wanted to run the plan past you guys for you input/opinion if that’s ok.

    The plan is for him to remove the 22mm gas pipe that’s sat on top of the two central heating and was buried under the concrete floor. To rerun it from the gas meter to the boiler - it can go trough my joists in a fairly pain free direct route and we’ve spotted. Sadly it does mean that we’d lose the gas feed to the front room fire but with a wood burning stove going in it’s just going to have to be one of those things. At least it’ll be safe not having the gas under the concrete any more.

    Then to change the two copper central heating pipes (which were buried in the concrete under the gas pipe) for plastic pipes, wrap with 9mm thick pipe insulation and then bury them back in the concrete.

    What do you think to that as a rough plan?

    His reasoning is that plastic for central heating is fine to burry and a thin layer of insulation (9mm) will stop some of the heat transfer in the floor etc.

    Your thoughts and help would be great please. Thanks.
     
  15. Combicert

    Combicert

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    There’s no issue with gas pipes in concrete if it’s done correctly - so seems a shame to lose the feed to the fire...

    But if you’re happy with the solution and you don’t mind losing the fire then happy days.

    Agree with the method described above
     
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