Insulating a loft

Discussion in 'Building' started by con1_uk, 24 Oct 2021.

  1. con1_uk

    con1_uk

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    Hi, I have chipboard along the centre of my loft for storage and the recommended thickness of wool in all other areas, understand I can’t install more under the chipboard as it needs to breath. What’s a good solution to insulate the loft properly but still have good insulation please? Any new products on the market? Would it be better to use Kingspan on the actual roof?

    Thanks.
     
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  3. JohnD

    JohnD

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    what is the depth of the loft joists?
     
  4. ^woody^

    ^woody^

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    It doesn't and you can
     
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  5. Catman Chris

    Catman Chris

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    Buy some stilts for your loft boards. Sold at B&Q. That way you can have insulation between your rafters and another blanket of insulation over that.
     
  6. con1_uk

    con1_uk

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    So I can pack it in under the chipboard floor?
     
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  8. ^woody^

    ^woody^

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    You may
     
  9. JohnD

    JohnD

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    ?
     
  10. con1_uk

    con1_uk

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    Standard 3inch pal
     
  11. JohnD

    JohnD

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    so you're limited to about 70mm of insulation if the floor is laid directly on top.

    If you add 250mm between the joists and squash it down with flooring, it becomes 70mm, so no advantage

    you can use stilts if you want, though my preference is to add cross-battens laid at right angles to the existing joists and lay your second layer of insulation between them. When screwed tightly down they will add rigidity and reduce the risk of cracking the ceiling plaster when you dance around up there.

    Another method was to lay rigid expanded foam on top of the joists and put your flooring on top (no battens required). This is simple but does not add rigidity. The foam makers used to include guidance on this method on their websites, but it seemed to disappear shortly after the Grenfell catastophe.

    I only use mineral wool inside my house, it is non-flammable.
     
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  12. phatboy

    phatboy

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    Instead of getting lengths of timber up there, with the associated weight, i got a kit from Loftzone (https://www.loftzone.co.uk/). Built quickly, and is about 250mm raised, so 200mm of insulation goes under properly and leaves an air gap.

    They will probably have a January sale, I got mine 25% off in a January.
     
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