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Warm deck-no vapour barrier but foil backed foam insulation

Discussion in 'Roofing and Guttering' started by damouse, 9 Sep 2014.

  1. damouse

    damouse

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    Location:
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    Country:
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    Hi all

    We're in the process of fixing up all the cr@p left to us by our long departed gorilla cowboy builders ... I can think of a few more choice names to call them but I won't

    Our roof is a mess - flat roof - quite large at 60 odd m2 covering back of the dining room, kitchen and study.

    The construction is a warm deck and the make up is as follows from top down.

    1. felt layer x 2 (not 3)
    2. plywood
    3. recticel foil backed foam insulation
    4. plywood deck
    5. joists
    6. standard plasterboard

    I'm having the whole of the felting removed and re-laid properly by a reputable roofer along with the lead flashing, fascias and some of he guttering ... its gonna cost a pretty penny or three. He won't be able to do this till late Nov though :(
    Meanwhile, we have tons of other things to get on with - kitchen installation in Oct, new flooring and other decorating and internals to take care of.

    But .. my mind is now turning to the roof and the fact that we don't have a vapour barrier below the foil backed insulation - i.e. on the warm side. I explained this to BC a while ago and they seemed to be quite happy with this - the foil acts as a barrier apparently.

    So now I'm in a quandary - I'm wondering if I'm best off asking the roofer to lift up the ply and the foam and re-lay all of it but with a vapour barrier first - sounds like a scarily expensive bit of work and probably more so very disruptive to the rooms below (more painting and plasterboard repairs?)

    Or am i over-worrying and should just wait and see how things go with regards to condensation - especially if BC are happy with this part of the roof build. We'll have a fairly hefty extractor fan in the kitchen and there are trickle vents in dining room and study so that will reduce the condensation risk I think?

    Wise words of wisdom much appreciated.
     
  2. Xenon

    Xenon

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    There should be a vcl to enable a sealed parcel to be made of the insulation. Preferably an aluminium lined vcl.
     
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  4. theoldun

    theoldun

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    Are your ceilings plaster boarded yet?
    oldun
     
  5. tygerbright

    tygerbright

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  7. damouse

    damouse

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    Hi Oldun - afraid so ... plaster boarded up, skimmed, and a first lick of paint. Also have lights up ...so the option to have foil backed plasterboard is out :(

    I'm having the BCO round next week for another review
     
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