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U values for loft conversion

Discussion in 'Building Regulations and Planning Permission' started by handyman77, 2 Dec 2013.

  1. handyman77

    handyman77

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    We have been informed by our private building control firm that our walls and ceilings must achieve a u value of 0.18. I was under the impression that was the recommended for windows and doors. We are now having to fit 100mm inbetween the joist and covering with a 40mm K7 this seems a bit belt and braces to me.....or is it just me?
     
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  3. freddiemercurystwin

    freddiemercurystwin

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    Yes ceiling is 0.18 and 100 Kingspan between and 40 under is required.

    Walls are 0.28 and 90 between the studs will get you there.
     
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  4. Architexeter

    Architexeter

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    Yep, thats the rules as the goverment is looking to the housebuilding industry to solve global warming.

    You are out by a factor of 10 with your impression of window u-values - they are more like 1.6 -1.8W/m2K not 0.18.

    I tend to spec 100mm on the walls and depending on rafter size ensuring adequate ventilation, 100mm between and 40+12.5mm insulated plasterboard to underside.

    You could look at multifoils such as Triso Super 10 as an alternative but this will still need some Kingspan.
     
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