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Warm Deck Flat Roof and PIR Insulation to get U-Value down to 0.12 or thereabouts

  • 03-08-2021 05:55PM
    #1
    Registered Users, Registered Users 2 Posts: 37


    I see that some PIR insulation brands are certified for use with warm deck flat roof type construction buildups but the thickness available seems to be a maximum of either 120mm in Kingspan TR24 or 150mm in Kingspan TR27. Any of ye on here have any experience in using 2 layers of PIR to increase the buildup without any issues in a warm deck flat roof of size 3m x 4m with a 3 layer torch-on finish? any issues with fixing the second layer of PIR? (total height of PIR will be 200mm or thereabouts).



Comments

  • Registered Users, Registered Users 2 Posts: 419 ✭✭Biker1


    150mm PIR will give you a U-value of 0.12w/m2k which is more than sufficient in this climate.



  • Registered Users, Registered Users 2 Posts: 37 CelicaGT


    Thanks for your thoughts on it Biker1 and taking the time to reply

    Yep, I was just thinking about that after I posted the question - it's far easier for me to use the 150mm PIR with the quoted thermal conductivity of 0.024W/m.K. The buildup of materials used together with the insulation should help me get my u-value down (the area is pretty small anyway and located over the entrance hall so it's not the end of the world if the u-value is at 0.13w/m2k or 0.14w/m2k), I'll get around to doing the u-value calculation at some stage and that will show what's being achieved.



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