Cavity wall insulation

Discussion in 'CycleChat Cafe' started by Trevrev, 12 May 2010.

  1. Trevrev

    Trevrev Veteran

    Hello peeps,
    I'm just looking onto having the cavities filled on my house, but i'm very unsure due to horror stories i've heard regarding damp problems after having it done.
    Has anyone on here had Cavity wall insulation? I'm sure some of you have!
    Any problems?
    I'm keen to hear good or bad, yes or no.
  2. Globalti

    Globalti Legendary Member

    Don't ask us muppets, go and ask on
  3. Manonabike

    Manonabike Über Member

    Actually, I was asking a friend of mine who is an structural engineer, the same question the other day. He said that cavity wall insulation is not a bad idea but for older buildings it might not be a good idea..... he was saying that he has seen older buildings having airways completely blocked with the insulation and creating massive problems. However, newer buildings don't seem to have that problem, the insulations stays inside the walls. An interesting thing he said is that having spoken to several so call experts on cavity wall insulation, most of them have no idea other than pumping the insulation inside the walls ...... :-)

    It's worth taking a look at the top of the walls and see where the wall insulation would go if it's allowed to overflow.
  4. Gerry Attrick

    Gerry Attrick Lincolnshire Mountain Rescue Consultant

    We had our bungalow insulated about three years ago by a company operating on behalf of a group of councils. Through the scheme we received a huge discount. The installers were very professional, and although they drilled seemingly countless holes through which to inject the fibre, it is very difficult to see them now.

    The end result is amazing in terms of heat retention. We are exposed to the nasty north and easterley winter winds, and before insulating we could still feel draughts even with the stove belting out heat. Now the stove merely simmers and we were warm and toasty even through this last winter.

    Get it done, you won't regret it, but ensure you use a thoroughly reputable set up.
  5. Mark_Robson

    Mark_Robson Senior Member

    We have a four bedroomed semi and it only cost us £100 ( including grants ) to get our house done three years ago and it has made a definite difference to our homes ability to retain heat, also we have had no issues with damp or condensation caused by the airbricks being blocked off.
  6. xpc316e

    xpc316e Senior Member

    I had my home insulated through a local council grant scheme a couple of years ago. It has made a vast difference to the general comfort of the house, and reduced the bills. There have been no prooblems with damp etc., although I am always mindful of opening windows in order to get some fresh air into the house.
  7. annedonnelly

    annedonnelly Girl from the North Country

    Mine was done ages ago - maybe 15 years - no problems at all with damp.

    Of course, there were no grants available then:sad:
  8. craigwend

    craigwend Grimpeur des Holderness

    No problems either, but is a newish house - has made a + difference as well.
  9. twentysix by twentyfive

    twentysix by twentyfive Clinging on tightly

    Over the Hill
    2 or 3 times in the last 25 years or so we have had sufficiently driven rain on one wall to cause damp to penetrate the cavity despite there being no cavity wall insulation. For that reason I'm very wary of having it done as the damp (under extreme conditions) does bridge the gap. But if there was no issue with the water proofing I'd have it done.
  10. OP

    Trevrev Veteran

    Thanks for your input people.
    We have a grant avaliable due to the age of our house, but i've heard, and read some horror stories of older houses, with porous brick work having massive problems with water penetrating into the insulation, and causing big damp problems.
    I've also talked to some builders that i know, and they all say the same, Cavities in older houses need to be kept clear as it helps the house breathe and keeps the wooden flooring up and down free from dry rot.
    So i thought i'd ask the question on here amongst my fellow cyclist to see if anyone has had any problems at all.
  11. dellzeqq

    dellzeqq pre-talced and mighty

    the key to this is the construction of the wall, and, in particular, the wall ties. You have to know that the fill material will not seperate the two leaves of the cavity as it swells to fill the cavity AND you have to know that the insulation will not corrode the wall ties. In general terms wool, cellulose, glass or rock fibre is the better bet.

    Sounds simple enough. It isn't. We're not very clever about building failures in this country, and it would pay to conduct a bit of research in to the corrosion of metal ties by foamed insulants on websites in the US before getting jiggy with the hose.

    The breathing cavity thing is, in broad terms, a myth. Sorry. I've been fully filling cavities for fifteen years, and it's very reliable BUT what you do need is a condensation calculation based on the construction of your wall, including finishes, before you proceed - and if you have a timber ground FLOOR then you must ensure that it remains ventilated.

    And you MUST get a guarantee backed by a major insurance company. And check your mortgage agreement before proceeding. And bear in mind that if you have a cavity that is continuous with your neighbour's you're going to have to block the junction.

  12. summerdays

    summerdays Cycling in the sun Moderator

    We've had cavity wall insulation for 15+ years ... I don't really notice the difference myself but when other people come into the house in winter time they often seem to assume we have the heating on when we haven't ... and we never turn the heating on before 1st Nov but that might just be in principle. I have noticed in summer it seems to trap the heat inside the house when we have a long hot spell.
  13. OP

    Trevrev Veteran


    Thanks for that advice......Have thought about the wall ties.
    Trouble is, the people trying to sell you this, aren't prepared to tell you the things to look out for. It's just sell, sell, sell !!
    More homework needed on this me thinks. We do have a timber ground floor and i do know our outer walls are very porous. I treat them with a water seal every two to three years to help.
  14. Dormouse

    Dormouse New Member

    I had mine done three years ago for £199. No problems with damp but I have not noticed any difference in heat retention so I can't say it is worth it. My energy use has actually gone up but that could be due to other factors unrelated to cavity wall insulation.
  15. albal

    albal Veteran

    i am currently surveying for cwi and lofts.EVERYONE is eligible for a grant.
    We get fines for booking in inappropiate properties. It's not in our interest to do the sell thing when a problem , ie damp amongst others is an issue.
    Current price £99. Nationwide.
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