If you have a new account but are having problems posting or verifying your account, please email us on [email protected] for help. Thanks :)
Hello All, This is just a friendly reminder to read the Forum Charter where you wish to post before posting in it. :)
Hi all, The AutoSave Draft feature is now disabled across the site. The decision to disable the feature was made via a poll last year. The delay in putting it in place was due to a bug/update issue. This should serve as a reminder to manually save your drafts if you wish to keep them. Thanks, The Boards Team.
Hello all! This is just a quick reminder to ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere.

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

  • 03-08-2021 5:55pm
    Registered Users Posts: 37 CelicaGT

    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).


  • Registered Users Posts: 290 ✭✭ Biker1

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

  • Registered Users 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.