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Should I add batts or loose fill above a 2 foot dropped ceiing?

John Loughran | Posted in GBA Pro Help on

I have a 100+ year old 4-square house with 2 courses of brick for walls. I’m planning on adding rigid foam to the exterior which will extend up to the eaves and the level of the original attic floor.

I’m planning to go to R-40 on the original attic flooring, but I’d like to keep the 2 ft. cavity created by the dropped ceiling accessible. Would it help to add batts or fill between the joists of the lower ceiling? Would any moisture problems be created between the two ceilings?

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    John,
    Before you add any insulation to your attic floor, it's essential that you perform air sealing work. The old ceiling (not the new dropped ceiling) should be your air barrier. All of your insulation should go on top of your air barrier.

    It's usually very hard to make a dropped ceiling airtight. That's why all of your insulation should go above the older ceiling.

    For more information, see Air Sealing an Attic.

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