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Discuss Pipes in Concrete Floor in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. Alex999

    Alex999 New Member

    Hello. Looking for a little guidance.

    Basically had a plumber install new ch system and radiators. He ran pvc pipes (2 22mm, 2 15mm and 1 copper gas main) with angle bends under the concrete floor. We’re now replacing the floor as it has no dpm or insulation and have found none of the pipes were wrapped or put in conduit with two angles just cemented in place. I’ve looked into conduit but cant seem to find anything to apply without disconnecting the pipes. My thought was to use some wood (wrapped in dpm) and create my own boxed in channel. This would give me access from the suspended floor in the room opposite to pull the pipes out if needed. My other thought was to use some sort of plastic square drain pipe turned over and placed on top then cemented over but getting a good fit seems difficult as the plastic is harder to find in different depths. Any help is greatly appreciated.

    Thanks
     
  2. Sparkgap

    Sparkgap Active Member

    From the sound of it you'd be best replacing with pipe-in-pipe. If you want to keep the existing but just form a duct around it with the wood you might have an issue in future because of the bends unless you make the duct large enough which then leads on to depth of concrete above the duct and whether it will be thick enough to prevent cracking. (If not you can use a screed with fibre reinforcement mixed in)
     
  3. Alex999

    Alex999 New Member

    Thanks for the reply. Dont really want to pipe in pipe if I can help it as to separate and cut all the pipes and re plumb and cover and really dont want to mess with the gas. The angle isnt very big so my thought was to box in all the way along to avoid going with the angles and just have two straight runs covered and wrapped in dpm. Could always add some chicken wire or stronger to strengthen above if needs be. Do you think the wood wrapped in enough dpm will be ok?
     
  4. Sparkgap

    Sparkgap Active Member

    I would avoid wood in solid floors. Whole load of issues in the future with rot etc. Plastic trunking would be better.
     
  5. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Any pics ?
     
  6. Alex999

    Alex999 New Member

    CC0B9B7C-A83E-44EA-B2B6-880B2E45E327.jpeg

    830AE350-45A9-4AB5-9A10-833F8E451098.jpeg

    49079522-2212-4899-9BCE-5552F9030375.jpeg
     
  7. Alex999

    Alex999 New Member

    Any idea on what sort of trunking? Something like PVC Maxi Trunking - 50mm x 50mm x 3m - White | ElectricalDirect

    I could snap over it. Issue is the angles..

    Thanks for the help!
     
  8. Alex999

    Alex999 New Member

    I’ve had a think and can replace all 4 pipes with full lengths. Take the cold supply into the boiler room and join there where its open and bring hot supply back for the kitchen sink! Should enable me to run all lengths in full with no connections in plastic sheathing/conduit to under the floor boards in the other room.
     
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Use some pipe insulation and gaffa tape all the joints
     
  10. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    Personally, I agree to do it properly with pipe-in-pipe will save you grief in the long term. The more joints you have underfloor the higher the risk of problems. Insulate those pipes and you will save a considerable sum over the years.
     
  11. richard978

    richard978 Active Member

    Firstly plastic does not need wrapping. The solution is to first consider under floor heating and the reality is it might be worth re routing the pipes.

    Some advice about concrete floors in old houses. If you put an in breathable membrane down it will force the damp up your walls. Better to use limecrete over compacted geocell glass beads.

    Limecrete | Glasscrete | Limecrete Floor | Breathable Floor System
     
    Last edited: Apr 11, 2019
  12. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    Richard. Somewhat misleading in a public forum if I may say. Most coming and viewing here will take posts far too literally and then whine about 'we told them wrong' when they receive their huge fuel bills. Personally I feel, as professionals, we have a duty of care to at least clarify what is written to minimise possible confusion.

    No underfloor system should be installed without substantial subfloor insulation. Any pipework running to and from over a non-insulated floor must be appropriately insulated to minimise losses and also to protect against potential frost.

    To do neither of those things simply demonstrates one is a comtemptable imbecile with no empathy for either fellow human beings or our planet.

    The OP is a good case in point. They have been told the right way to do it but you can see in the replies their reluctance. All too often on here we get folk coming on looking for nothing but confirmation that their idea is 'right'. They often get the hump when a different but correct route is pointed out. Let's hope this poster takes our advice for what it is - practicable. If they do, they are guaranteed to fit and forget, if they don't then they spin their coin not me ;)
     
  13. richard978

    richard978 Active Member

    Hence the reference to limecrete floors. It's the only way it should be done in old homes with no dpc. Insulation comes from the glass, you don't need anything else and putting down modern non breathable membrane and concrete will destroy the bricks as all the moisture and salts get pushed up.
     
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