1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Regs for floor and roof insulation?

Discussion in 'Building Regulations and Planning Permission' started by d000hg, 4 Sep 2019.

  1. d000hg

    d000hg

    Joined:
    17 May 2013
    Messages:
    875
    Thanks Received:
    4
    Country:
    United Kingdom
    We've constructing a 11.5x6.5m log cabin, which sits on a wooden raft (suspended floor basically). When we got quotes to insulate the floor with 150mm kingspan boards, we were taken aback to see materials costs quoted £2-3k!

    I'm wondering what the minimum insulation we can actually get away with. Is it based on u-values?

    If we mentioned the insulation type in our planning application, will anyone care if we modify this if it still meets regs?
     
  2. cdbe

    cdbe

    Joined:
    22 Nov 2009
    Messages:
    421
    Thanks Received:
    47
    Location:
    Oldham
    Country:
    United Kingdom
    100mm would be ok, or get onto ebay:

    Screenshot_20190904-185912.png
     
  3. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    26,281
    Thanks Received:
    3,240
    Location:
    West Mids
    Country:
    United Kingdom
    Yeah, no one cares what you use.
     
  4. Leofric

    Leofric

    Joined:
    9 Nov 2018
    Messages:
    1,237
    Thanks Received:
    106
    Country:
    United Kingdom
    You don't need to mention thermal insulation in your planning application. Thermal insulation and U values come under Building Regulations but calculations relating to these things involve more than just one element of the building, if that makes sense. What will the log cabin be used for ?
     
  5. d000hg

    d000hg

    Joined:
    17 May 2013
    Messages:
    875
    Thanks Received:
    4
    Country:
    United Kingdom
    I think building regs will require the cabin overall be thermally efficient as it has a business purpose (hence the planning application in the first place).

    If it's based on various things, how can we be sure to meet regs if there aren't objective criteria we can measure?!

    It's going to be used for garden based childcare business.
     
  6. Leofric

    Leofric

    Joined:
    9 Nov 2018
    Messages:
    1,237
    Thanks Received:
    106
    Country:
    United Kingdom
    That is where people like architects and architectural technicians come in useful to prepare building regulations applications, and they will most likely use energy rating consultants for calculations on heat loss etc. You can view the Building Regulations Approved Documents on the LABC or Planning Portal websites but they aren't something the layman can really be expected to understand that well.
    I would recommend a Full Plans Submission for bldg. regs approval, assuming you obtain planning permission.
     
  7. d000hg

    d000hg

    Joined:
    17 May 2013
    Messages:
    875
    Thanks Received:
    4
    Country:
    United Kingdom
    Planning is granted, we're getting quotes. Not having dealt with regs before we've been putting it off but you're probably right... Better to get started early than try to rectify things later?

    We have a book on regs but I'd hoped this was an area you could clearly demonstrate you'd met the required U values, or whatever. Guess not, but still it's be helpful if anyone can advise what's normally used/required in a new building for floor and roof.

    The walls are solid wood, 65mm think. So quite insulated but not up there with modern cavity walls... We figured making up for that elsewhere was a good idea. Eg we upgraded the cabin windows to proper double glazed units.
     
  8. Leofric

    Leofric

    Joined:
    9 Nov 2018
    Messages:
    1,237
    Thanks Received:
    106
    Country:
    United Kingdom
    you can show you are achieving certain U values for walls, floor and roof but there is more to it than that, as there is more to bldg. regs than just thermal insulation, but can't go into everything on here.
     
  9. Nige F

    Nige F

    Joined:
    28 Jun 2005
    Messages:
    19,852
    Thanks Received:
    1,449
    Country:
    United Kingdom
    Maybe that will put a different slant on the insulation used ? Sheep's wool non alergenic finish etc.
     
  10. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    26,281
    Thanks Received:
    3,240
    Location:
    West Mids
    Country:
    United Kingdom
    Insulation is not just thought of in isolation, but should form part of an overall design strategy. Type of walls/floor/roof, materials and construction should all influence the choice of how to acheive (or better) the required u-values. Certainly not a case of "What can I throw in the floor and ceiling?"

    I'd concentrate a bit more on fire safety though, if this is has commercial useage.
     
    • Like Like x 1
  11. Leofric

    Leofric

    Joined:
    9 Nov 2018
    Messages:
    1,237
    Thanks Received:
    106
    Country:
    United Kingdom
    Yes, that is what I was trying to get across.
     
  12. noseall

    noseall

    Joined:
    2 Feb 2006
    Messages:
    34,438
    Thanks Received:
    2,156
    Location:
    Staffordshire
    Country:
    United Kingdom
    You are constructing a building with a footprint area of over 70sq/m and you are fretting over a couple of grand for insulation? A building of that size - be prepared to see material costs in their £000's often.
     
  13. IT Minion

    IT Minion

    Joined:
    28 Jul 2018
    Messages:
    111
    Thanks Received:
    8
    Country:
    United Kingdom
    That comes out at £28-£42 a square meter. 150mm boards from B&Q cost around £31 a square meter, excluding any wastage. Not obviously taking the **** but to echo earlier points that's a hell of a lot of insulation for a floor.
     
  14. d000hg

    d000hg

    Joined:
    17 May 2013
    Messages:
    875
    Thanks Received:
    4
    Country:
    United Kingdom
    Indeed. I don't remember where we got 150mm from. Is that not what is used as standard in new build roof insulation?
    Regs aside, what would typically be used for floor and roof insulation in a new house just for comparison?
     
  15. ^woody^

    ^woody^

    Joined:
    3 Sep 2006
    Messages:
    26,281
    Thanks Received:
    3,240
    Location:
    West Mids
    Country:
    United Kingdom
    It depends on the design.

    You need to broaden your thinking and not be fixated on insulation thickness.
     
Loading...

Share This Page