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DPM on old car port base 5x4m

Discussion in 'Floors, Stairs and Lofts' started by Dain1, 14 Jun 2019.

  1. Dain1

    Dain1

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    I blocked up the old car port to convert it domestic use. It has a membrane under the conc slab but building control say I also need a dpm over the slab and slightly up each wall: makes sense I suppose, it'll have a plywood floor + engineered wood, on battens.

    What type of membrane do I need?

    There are a few slightly odd corners, and I will need stud/insulation on inside faces of some of the walls. It would be handy if I could get some membrane down around the outside of the room and joint a centre piece in later to preserve access for a while and prevent membrane damage during works, if some sort of jointing tape was available. How are joints created in DPM, are they rolled or taped joints?

    I imagine that running the memrane up the wall in an inside corner would be easy enough to accommodate with a fold or two in the corner, but an external corner would need some sort of tape?

    Do I need to protect the membrane with geotextile?
     
    Last edited: 1 Jul 2019
  2. Notch7

    Notch7

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    My guess is that the original membrane sat underneath a concrete slab and there is not way to connect it to the walls.

    I think that because generally dpm would not be required below a suspended floor.

    Standard 1200 gauge plastic dpm is fine. If it is an awkward shape, a liquid dpm is an alternative.

    You can join dpm, use a 600 lap mm and use tape. I think ideally it should be folded, but thats easier said than done with thick polythene so I just say a big overlap works.

    You can buy tape for it. Or the super sticky gorilla tapes works. Dont use ordinary duct tape
     
    Last edited: 15 Jun 2019
  3. Dain1

    Dain1

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    Not actually floating, I don't think I got that right: engineered wood on 18mm ply, on firrings or batten.
     
  4. foxhole

    foxhole

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    Liquid Dpm .
     
  5. Dain1

    Dain1

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    Maybe the void neneath the ply base will be enough to accommodate a folded joint.

    I'll leave a meter or so out front of the baseplate, so I can do either.
     
  6. Dain1

    Dain1

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    Sika Rapid 5 litres for £70 which conveniently doesn't seem to be a 2 pack, so maybe I could just do where the sole plates are going with that and finish the rest of the base later.

    Coverage seems to ok with 5 litres providing 2 coats over 20m².

    Has anyone ever used it?
     
    Last edited: 12 Aug 2019
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