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Timber Ceiling Joists

  • 08-01-2023 8:56pm
    Registered Users Posts: 11

    Hi All,

    We have gone for timber ceiling joists instead of Ducon slabs for our story and a half. Should i treat the joist ends where the will sit on inner leaf of block. Also what's best option for sheeting out the joists, will OSB get destroyed when exposed to weather for upto 2 months?


  • Moderators, Home & Garden Moderators Posts: 10,140 Mod ✭✭✭✭BryanF

    put the Joists on hangers. And figure out your air-tightness layer/strategy before doing anything.

  • Registered Users Posts: 757 ✭✭✭C. Eastwood

    There is absolutely no need to treat the ends of the timber above DPC with preservatives.

    However, after a short period of time the joists will dry out to a lower moisture content, which will result in shrinkage and cause a gap of approximately 1 mm at the sides and top of each joist- which will allow draughts and result in heat loss by Convection.

    I agree with the recommendation above - fit metal joist hangers.

  • Registered Users Posts: 386 ✭✭grimeire

    Timber is always supposed to be threated or wrapped in dpc when in contact with concrete.

    Hangers is what you are supposed to use for air tightness but they are expensive. They are also slower to fit.