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Cavity wall insulation - how long does it last?

My 2-bedroomed detached bungalow was insulated with mineral wool by Rentokil 33 years ago and was guaranteed for 30 years. I qualify for free cavity wall insulation and am wondering whether to take advantage of a free home survey or is it better to assume that it is still o.k. I have no idea whether it deteriorates over time. Does anyone know please?


  • punknzippy
    not to sure about deteriation of the mineral wool but i do know that after 33 years it might have settled in the cavity leaving gaps where its not insulated so considering its free . . . . . a top up surely couldnt hurt
  • latecomer
    latecomer Posts: 4,321 Forumite
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    I wondered the same but haven't been able to find any information on it. And I'm not sure how a topup would work as unless its under quite a pressure I dont see it displacing any of the existing insulation to fill in the gaps?
  • Petrarch74
    Hi, Rockwool Energysaver cavity insulation has been proved in service for 40 years and should provide effective insulation for the lifetime of the building. Do you know if it was glass or stone wool? Check out the Rockwool website.
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