Draught proofing a chimney breast with loft insulation boards?

Discussion in 'General DIY' started by Sharpey, 1 Feb 2016.

  1. Sharpey

    Sharpey

    Joined:
    15 Dec 2009
    Messages:
    187
    Thanks Received:
    0
    Location:
    Kent
    Country:
    United Kingdom
    Hello all.

    I have a front room with two open chimney breasts. I am concerned these are making the rooms really cold. Also, I am going to be using a dehumidifier in these rooms so I want to minimise the amount of the external air being pumped in to the room.

    To block them, I was thinking of getting some Celotex board, cutting it to size, and laying it flat horizontally in the chimney (it has internal bricks either side that can support the boards). I could leave the back edge slightly shorter to allow some ventilation or just cut a hole in the middle of the board.

    In theory this should greatly reduce the amount of draughts whilst still allowing the chimney to breathe. Is this a good idea or does anyone see potential shortcomings in this method? Will a Celotex board provide adequate insulation?

    I am reluctant to go for chimney balloons as they are expensive and have mixed reviews.

    I should add, both chimneys are unused and won't have any fires being lit.
     
  2. Sponsored Links
  3. foxhole

    foxhole

    Joined:
    14 Mar 2006
    Messages:
    18,238
    Thanks Received:
    2,094
    Location:
    Kent
    Country:
    United Kingdom
    You can use any board, non will provide insulation, just reduce air flow.
    Is £12 expensive for a balloon? you could use a lump of rigid rockwool stays put without a shelf.
     
  4. Sharpey

    Sharpey

    Joined:
    15 Dec 2009
    Messages:
    187
    Thanks Received:
    0
    Location:
    Kent
    Country:
    United Kingdom
    Hi foxhole, thanks for replying.

    The chimney balloon that fits my chimney is £25, I need two. It has some terrible reviews, so I don't really fancy paying £50 for something that might not even work. I think it's another £11/12 for the pump to inflate it as well.

    I don't mind what type of insulation used if there is not a huge difference between them as most should be easy enough to lodge in there. But in theory is the principle OK, as in draughts will be reduced, room will become warmer?
     
  5. chappers

    chappers

    Joined:
    27 Aug 2004
    Messages:
    3,254
    Thanks Received:
    357
    Country:
    United Kingdom
    use a chimney sheep rather than a balloon , they don't need inflating. and also allow a bit of airflow still
     
  6. foxhole

    foxhole

    Joined:
    14 Mar 2006
    Messages:
    18,238
    Thanks Received:
    2,094
    Location:
    Kent
    Country:
    United Kingdom
    Why are you needing a dehumidifier, ventilation is free.
     
  7. Sharpey

    Sharpey

    Joined:
    15 Dec 2009
    Messages:
    187
    Thanks Received:
    0
    Location:
    Kent
    Country:
    United Kingdom
    I need a dehumidifier because the internal walls are suffering from damp. It's not penetrating damp. It's been like this for two years and nothing seems to fix it, opening windows or anything, in fact it seems to get worse.

    This will set me back around £100 for what I need so I'm going to pass on them.
     
  8. Sponsored Links
  9. foxhole

    foxhole

    Joined:
    14 Mar 2006
    Messages:
    18,238
    Thanks Received:
    2,094
    Location:
    Kent
    Country:
    United Kingdom
    If having an open chimney does not dry out a wall over two years then it's far beyond a humidifiers capacity.
    You need to cure the damp source, what makes you so sure it's not penetrating damp?

    A few pics might help identify the problem.
     
  10. Sharpey

    Sharpey

    Joined:
    15 Dec 2009
    Messages:
    187
    Thanks Received:
    0
    Location:
    Kent
    Country:
    United Kingdom
    They're internal walls, so I don't think it is penetrating. The moisture didn't start at the bottom so it's not rising (assuming that even exists because it is disputed)

    The dehumidifier does seem to be improving matters.

    I think it is a combination of salts in the wall and internal excess moisture, and cold spots on the wall, all creating a perfect storm. It seems to have happened after the place was replastered. Prior to that it was lining paper on the walls and this might have provided some insulation as the damp didn't appear in the same spots then.

    I posted a thread on it a while back with pics, consensus was to leave it and see how we got on but it never got better after leaving it, it got worse

    http://www.diynot.com/diy/threads/weird-internal-damp-problem.392663/#post-3025550
     
    Last edited: 2 Feb 2016
  11. foxhole

    foxhole

    Joined:
    14 Mar 2006
    Messages:
    18,238
    Thanks Received:
    2,094
    Location:
    Kent
    Country:
    United Kingdom
    The walls are adjacent the external wall and window which could have voids around it allowing in moisture, I see you had a damp proof company in [never a good idea] seems they have made things worse by not identifying the source and then making it worse with there work.Salts are washed thru the brickwork so you still have penetrating damp.You also mention a porch in OP so may have poor roof covering/finish letting in rain.
     
  12. Sharpey

    Sharpey

    Joined:
    15 Dec 2009
    Messages:
    187
    Thanks Received:
    0
    Location:
    Kent
    Country:
    United Kingdom
    Thanks for the advice. The porch is closed off, it has two front doors. The damp in the hallway is on the internal door side. As for the living room, the damp wall isn't directly next to the window and I just don't see where from the window there can be a penetration of sufficient water that somehow migrates to a wall a foot away. There are no cracks or anything on the wall directly outside.

    [​IMG]

    Pretty much that entire bottom foot of plaster was hacked off by the damp company and replaced with their damp proof plaster or whatever. The right hand side underneath the window was the where the original damp was, that has now gone and you can see the new spots developing. Perhaps whatever the original source of the damp was still exists, is avoiding the special plaster and migrating upwards and settling above like in the pictures?
     
  13. foxhole

    foxhole

    Joined:
    14 Mar 2006
    Messages:
    18,238
    Thanks Received:
    2,094
    Location:
    Kent
    Country:
    United Kingdom
    Difficult to defy gravity, tends to fall thru the structure from above.
     
  14. 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