How to insulate ceiling under flat roof?

Discussion in 'Building' started by beefster, 9 Sep 2010.

  1. beefster

    beefster

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    I am looking to convert a side extension / store room with flat roof and no heating into a living space / office.

    Have checked the roof and no insulation at all. What would be the best way to insulate the ceiling which is currently plasterboard.

    Just putting in a new heating system in and want to add a rad to this area which was a farm shop on side of house.
     
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  3. beefster

    beefster

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    Anyone...
     
  4. mointainwalker

    mointainwalker

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    How deep are the joists carrying the plasterboard ?
     
  5. beefster

    beefster

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    9 inches. Maybe a little more?

    What are you thinking?? Kingspan between joists??
    Was wondering about a vapour barrier? Where to put it?

    would this be right working down.
    Felt
    roof boards
    air gap - poss add breather vents in each run. None at present? needed?
    insulation board
    re - plastr board.

    Where doeas the vapour barrier go?
     
  6. noseall

    noseall

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    Either add a warm deck system above the joists or, if you can ventillate, use insulation between and below the joists.

    Any vapour barrier will need to go directly behind the plasterboard.
     
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  8. alittlerespect

    alittlerespect

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    Hi

    Easiest solution would be to 'stick n fix' 100mm of PIR insulation to the top of the existing roof and re-felt (asssumes that you have enough of an upstand).

    May require the flashing to be raised.

    Otherwise job done and not a lot of mess!

    Regards
     
  9. ^woody^

    ^woody^

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    Just bung 9" of quilt between the joists and then use foil backed plaster boards. Old skool :cool:
     
  10. mointainwalker

    mointainwalker

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    woody

    Not old skool but simply the easy, cheap, labour-saving , intelligent method.

    Exactly what you look for in a solution.
     
  11. beefster

    beefster

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    Just getting around to this part of the project.

    Queries.
    I assume foilbacked boards act as vapour barrier. What do i do at joints to seal it?

    Re 9 inch quilt, How best to hold it up in between the joists before boards go on?

    Ta
     
  12. DIYnot Local

    DIYnot Local

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    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

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