Celotex on internal walls

Discussion in 'Eco Talk' started by DannyDoLittle, Jul 23, 2017.

  1. DannyDoLittle

    DannyDoLittle Member

    Afternoon all..

    The property I'm about to get the keys for is a 1970's dormer bungalow and is single skin brickwork in some places..

    To insulate the house more, can I baton Celotex to the walls and board straight over them and plaster directly on the boards??

    Doing a bit of digging it seems around 75mm boards would be sufficient, but need to be sure that it'd be fine. I'll also be putting up a few partition walls and will be insulating with Celotex within these walls..

  2. Are the external walls in good condition and not allowing damp penetration?

    Good, then chust Dot and Dab insulated plasterboard - essentially Celotex with p'board bonded to it - straight on to your walls.

    Peasy and will transform your insulation levels.

    Fit whatever thickness you can afford and get away with, but really no need to go beyond - ooh - 45mm insulation layer, so 55mm overall thickness (plus ~10mm dabs).

    For internal walls, don't bother with insulation unless it's for sound proofing. You don't need to thermally insulate internal walls - where's the heat gonna go - in to the next room?!
    longboat likes this.
  3. DannyDoLittle

    DannyDoLittle Member

    Yeah the internal walls are in good nick, no issues there. As for the internal walls, it's only really one new studded wall that i'll be using Celotex in because I'm dividing a large L Shaped lounge up and creating a good sized double room in what is currently the L, so will have a lounge area directly behind that wall. With regards to this wall, I'm thinking about making it wider, as in.. instead of going with the usual 2x4 frame work, I'll use 6x2 and add more insulation / soundproofing.. Is it worth it??
  4. 4x2 is perfectly adequate for internal stud walls - in fact many try and get away with 3x2. Unless there is a particularly good reason for going 6x2 - super strength or high sound insulation - I wouldn't bother.

    As I said before, there is no usually need to add thermal insulation to INTERNAL walls because both sides of the wall will be at basically the same temp - so no heat transfer.

    Sound insulation is a different matter, of course, and this SHOULD be considered especially when it's bathroom, bedroom or noisy reception rooms - blaring TVs, etc.
  5. DannyDoLittle

    DannyDoLittle Member

    The studded wall in question... one side will be a bedroom, the other will be a lounge area and the TV will be right next to the wall, so sound proofing is a must have... a bit unfair having a TV blaring when there's people in the bedroom.

    Cheers anyway pal.. appreciated the info ;)
  6. In that extreme case, I would do some research on the best forms of insulation. It may be that two thinner 'skins' - separated by an air gap - would work best, but worth investigating.
    DannyDoLittle likes this.
  7. DannyDoLittle

    DannyDoLittle Member

    Cool.. cheers pal, will look into it.
    Deleted member 33931 likes this.
  8. Bob Rathbone

    Bob Rathbone Well-Known Member

    If I had a single skin wall in the house I would treat it as you would a timber framed construction, but in reverse. You need to build an inner wall with wood and ply to replicate the methods used in modern timber framing. You will have ties between the wall and wooden frame, with a one way vapour barrier, the ply and the batons. You can then fit insulation and a vapour barrier and plasterboard over. It will not be easy doing *** about face but it will give the best results.
    DannyDoLittle likes this.
  9. GoodwithWood

    GoodwithWood Active Member

    When it comes to soundproofing considerations remember what you are trying to reduce is transfer of vibration from one room to another. Insulation will help but there are far more effective methods.

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