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Insulation above a t-bar suspended ceiling?

user-991559 | Posted in Energy Efficiency and Durability on

Create an insulated office within a larger warehouse space. Warehouse is 18′ floor to roof deck, clients want 10′ t-bar ceiling for new office space.

Issue: how to insulate…
Existing building is poorly insulated, thus need to create insulated ceiling above office.

Thus far, ideas include installing Owens Corning Sonobatt directly over the t-bar ceiling.

Or creating a 2′ conditioned plenum between the t-bar and a separate insulated structure (such as hanging from the existing roof OWSJ a lattice of 2″x2″ at 2′ o.c. each direction. Then laying 8″ batt insulation above it, and stapling 6 mil poly below.

My thoughts are that putting Sonobatt directly over the t-bar will not work – aside from poor service access, there will be no air-barrier between the conditioned office space below and the non-conditioned air above the t-bar. The air will pass right through the batt.
Not to mention condensation issues (warm/humid office air going up through t-bar ceiling into the batt insulation and condensing).

Is the second solution the best idea?

The project is in Toronto, Canada.

Thanks for any guidance.


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  1. GBA Editor
    Martin Holladay | | #1

    You're right - you can't install batt insulation on top of a suspended ceiling, because you wouldn't have an air barrier.

    There are lots of ways to do this, but the best way is with ceiling joists and drywall. If the customers want a suspended ceiling, put the suspended ceiling below the drywall. At least that way you'll have an air barrier.

  2. user-991559 | | #2

    Thanks Martin,
    Great to have my intuition backed up, much appreciated!

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