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Insulating boarded attic

Discussion in 'Home and Garden' started by Ahleckz, 14 Oct 2021.

  1. Ahleckz

    Capodecina

    Joined: 7 Nov 2009

    Posts: 18,663

    Location: Glasgow

    My attic is boarded, and from a quick glance today it has around 10cm of insulation under the boards. I think I have room to basically double that.
    I understand I shld have at least 27cm but I’d then have to raise the floor and I don’t want to do that.

    Is this as simple as unscrewing the wooden panels and rolling the insulation out and putting the boards back in? Am I missing something obvious here?

    I know I don’t want to squish the insulation down as it lowers it’s effectiveness but I’m sure my solution should be useful.

    also, where should I buy insulation?
     
  2. Mel_P

    Wise Guy

    Joined: 27 Feb 2004

    Posts: 2,331

    Location: Kent

    Last edited: 14 Oct 2021
  3. Peerzy

    Soldato

    Joined: 9 Nov 2008

    Posts: 6,952

    I did this recently to my loft (well, about a year ago). You need to raise the loft floor, I did this with Loft Legs from Wickes. Dead easy to use and get hold off. I also found Wickes was the best for new boards and insulation.

    Don't add more insulation below existing boards as squishing it down means it doesn't work anywhere near as well. You could just lay it on top of your existing boards but you'll obviously lose the ability to store anything up there.
     
  4. Derek W

    Capodecina

    Joined: 1 Oct 2008

    Posts: 11,786

    Location: Glebe Park

    Just get as many rolls of wool insulation like knauf vearlthwool loftroll 44 as you need to cover your loft. Packs of the 100mm so you don't need to add stilts as you don't want to. Avoid anything with a foil though as I've had a builder in the past install a kingspan type board which has caused interstitial condensation which ruined the ground floor ceiling as the cold air hit the foil and formed water droplets

    Just shop around at the main DIY places to see what the cheapest is for whichever wool you want to use
     
  5. Yaayuh!

    Capodecina

    Joined: 5 Nov 2010

    Posts: 21,854

    Be sure not to compress the insulation too much (or at all really).

    Lift boards and put them on legs as suggested, or add more boards on top, but that seems a waste to me.
     
  6. The1nonly1

    Wise Guy

    Joined: 24 Jul 2009

    Posts: 1,755

    Location: Stoke-on-Trent

    Like others have said, raise the floor using loft legs for more insulation. I used the Loft legs XL and they were really easy to install and screw the boards into.
     
  7. Buffman

    Sgarrista

    Joined: 4 May 2007

    Posts: 8,194

    Location: West Midlands

    Why don't you want to add boards / increase the height? The best way as mentioned is to use a boarding system and raise the level.

    The reason there may current be a "gap" of approx 100mm is to prevent interstitial condensation - I'm not sure if it needs to be 100mm but id be hesitant to pack it full. - saying that I packed under boards in my old house full of insulation :p (this one I think i will try leave a gap but never saw issues with previous one)
     
  8. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,375

    Location: Berks / Moscow

    125mm CLS across at 90 degrees will give you a total 225mm gap which is much better than 100mm. The boards also then stop airflow pulling warm air out of the insulation. Obviously you lose some ceiling headroom so consider that

    wood is expensive at the moment but I don’t like loft stilts , just did this at a mates house. Rock solid
    [​IMG] [​IMG] [​IMG] [​IMG]
     
  9. Ahleckz

    Capodecina

    Joined: 7 Nov 2009

    Posts: 18,663

    Location: Glasgow

    Ugh, I know I should raise the floor but just seems like a load of hassle and extra money. I was just hoping to unscrew the boarding, throw some insulation down and screw the boards back in. Thought I could get that done in a few hours. Putting in raisers just adds to the cost and time.
     
  10. Peerzy

    Soldato

    Joined: 9 Nov 2008

    Posts: 6,952

    If you only have 100mm at the moment and there is 200mm space then do what you suggest, it won't be as good as raising the floor to put about 300mm in but it's better than your existing situation. Just remember that squashing any of it down to get it in is pointless and a waste of time, so only fill the actual space you have.

    Remember to do all areas - including the loft hatch.
     
  11. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,375

    Location: Berks / Moscow

    200mm will be enough. Huge benefit from
    100 as said. Google a chart
     
  12. SPG

    Sgarrista

    Joined: 28 Jul 2010

    Posts: 7,780

    Take all your insulation out, phone your energy supplier they will come and do a survey and book a date for free insulation.

    In the meantime install loft legs, installer comes and installs free insulation all you need to do is put the boards on the loft legs.

    :)
     
  13. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,375

    Location: Berks / Moscow

    Are there any energy suppliers left ?

    I did that a few years ago when British Gas offered it. But it was government backed and finished now I’m sure unless you are on benefits etc ?
     
  14. SPG

    Sgarrista

    Joined: 28 Jul 2010

    Posts: 7,780

    I did exactly the same thing, loft insulation was one of the things open to all for change everything else you had to tick all the right boxes I think.