Insulated plasterboard, how much difference will it make to solid brick walls?

Discussion in 'Building' started by MisterBoy, 28 Jan 2021.

  1. MisterBoy

    MisterBoy

    Joined:
    9 Jan 2020
    Messages:
    418
    Thanks Received:
    8
    Country:
    United Kingdom
    My house is ~1860 with solid walls. My home office has two external walls and in colder months, I get a cold draft washing down the walls which leads to very cold feet :)
    I wondered about interior cladding with PIR-backed plasterboard, it's 25mm insulation on 12mm plasterboard.

    Maths or more anecdotal answers welcome, I don't need the room to be super efficient just to avoid icy-cold walls which also risk condensation/mould problems. Would this make a significant improvement to my solid brick?

    Ta.
     
  2. Sponsored Links
  3. Mr Chibs

    Mr Chibs

    Joined:
    28 Jul 2015
    Messages:
    1,091
    Thanks Received:
    182
    Country:
    United Kingdom
    Can't speak for 25mm, but 50mm will make a world of difference, I've lived in old property no insulation and current old house has 50mm internal insulation and it's fantastic.
    Do the floor too if you can, with rockwool to save some lolly.

    It's cheaper to buy the insulation and plasterboard as separates if required, plus you get double sided foil barrier when done this way.
     
    • Like Like x 1
  4. MisterBoy

    MisterBoy

    Joined:
    9 Jan 2020
    Messages:
    418
    Thanks Received:
    8
    Country:
    United Kingdom
    Done the floor already - there is a cellar under so we put PIR between the beams when re-doing the ceiling down there. 100mm from memory.
     
  5. Mr Chibs

    Mr Chibs

    Joined:
    28 Jul 2015
    Messages:
    1,091
    Thanks Received:
    182
    Country:
    United Kingdom
    Good, you're good to go then... my whole house has been done, it's very warm and even in the last couple of weeks, won't go below 16/17° overnight, once the heating has gone off at around 10pm (heating set to 19°)
     
  6. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    75,030
    Thanks Received:
    4,350
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    Yes.
     
  7. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    75,030
    Thanks Received:
    4,350
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    Measure the exterior wall area in square metres. For ease, assume a 20C difference between indoor and outdoor temperatures.

    Look up U- values

    https://www.greenspec.co.uk/building-design/u-value-introduction/#:~:text=The technical name for which,the inside and the outside.

    Also
    https://www.gov.uk/government/publi...at-losses-and-the-potential-for-energy-saving

    There might be a simpler webpage somewhere.

    There are bound to be variations and inaccuracies but it will give you a pretty good idea.

    You can knock off the old plaster first if you want.

    A wooden frame is not necessary.
     
  8. Sponsored Links
  9. howbut82

    howbut82

    Joined:
    30 Aug 2020
    Messages:
    13
    Thanks Received:
    3
    Country:
    United Kingdom
    Personal experience... using the 38mm board from wicked, within a corner box room, wall surface temperature increased from 14 to 19 degC on a cold day (external 5C).
    Hugh difference from the radiation heat transfer perspective. Best £150 I spent to be honest.
     
    • Thanks Thanks x 1
  10. MisterBoy

    MisterBoy

    Joined:
    9 Jan 2020
    Messages:
    418
    Thanks Received:
    8
    Country:
    United Kingdom
    Very helpful, cheers for that.
     
  11. howbut82

    howbut82

    Joined:
    30 Aug 2020
    Messages:
    13
    Thanks Received:
    3
    Country:
    United Kingdom
    To achieve Building Regulations 0.30 U-Value, you will need to use the 62.5mm board (Kingspan K118 or similar).
    Once you hit that high U-Value, make sure all gaps are sealed with tape to maintain the vapour seal, otherwise, there is a risk of condensation (and mould) form between the insulation and internal brick face.

    The K118 technical datasheet gives quite good instruction regarding detailing.
     
    • Thanks Thanks x 1
  12. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    75,030
    Thanks Received:
    4,350
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    The first inch of insulation saves a lot more energy than the second inch.
     
  13. Uses a lot more too.
     
  14. Rad1o

    Rad1o

    Joined:
    27 Jun 2012
    Messages:
    278
    Thanks Received:
    13
    Location:
    Leics
    Country:
    United Kingdom
    We moved into a house - 1930ies with solid walls - with an extension - 1970ies with cavity wall insulation. The house had always been cold while the extension felt a lot warmer. I have insulate all the rooms in the house with 50 to 60mm dry wall insulation from Kingspan or Celotex depending on price at the time. The house is very different now. Take pictures when you do it for future energy certificate purposes.
    I have also changed windows and the outside doors to frame insulated and triple glazed parts. Another big difference.
     
    • Like Like x 1
  15. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    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.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Loading...

Share This Page