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Forums Forums GARAGE CONVERSION FORUM UK Warm flat roof over garage conversion

  • William Allen

    Member
    December 26, 2025 at 10:16 am

    150mm aiming for u-value of 0.18Wm2k

  • Mia Baker

    Member
    December 26, 2025 at 10:17 am

    Thankyou Can 100 mm go above and 50 mm push uptight to underside Osb be compliant so no air flow

  • William Allen

    Member
    December 26, 2025 at 10:17 am

    that’s a hybrid roof but it’s not fully tested yet, I’m not going to hold my breath.

  • Mia Baker

    Member
    December 26, 2025 at 10:18 am

    So if I’ve got 150mm joists with flat roof use 100mm insulation to bottom of joists and use a vapour barrier before plasterboard?

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