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Community and Q&A

Insulating Shared Wall Between Garage and Kitchen

KYbill | Posted in General Questions on

The 2×4 wall between our [enclosed] garage and house (kitchen in this case) is uninsulated, making the kitchen wicked cold in the winter. I want to tear out the wall from the garage side, insulate, and rebuild the wall. For insulation I am thinking to use mineral wool batts. We are in region 4A.

Given that the wall is under the roof, the easiest sheathing option would seem to be regular OSB, but that doesn’t seem to significantly reduce thermal bridging at the studs. I only need 7, 4×8 sheets of whatever I choose, so I’m open to using other materials or multiple layers so long as I don’t create too much more work for myself. There are some electrical conduits attached to the garage side of the wall that might become an issue if the garage-side thickness changes too much.

Anything is better than what’s there now of course, but I would appreciate feedback on anything I’m missing or could do better.

Thanks in advance, Bill.

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  1. GBA Editor
    Kiley Jacques | | #1

    Hi Bill,

    A similar question from a neighboring Connecticut reader might be of interest to you. In this Q&A thread, Martin Holladay weighs in on two scenarios:

    1. Roxul in the stud bays, polyiso sheets over the studs, and firecode sheetrock over that

    2. Polyiso cut to fit into the stud bays, spray foam in the gaps, Roxul to fill, foam over the studs, and sheetrock

  2. KYbill | | #2

    Thanks for the response Kiley. Didn't find that thread before posting sorry. Best, Bill.

  3. user-6184358 | | #3

    The wall between the garage & house need to be fire rated ! So, 5/8" drywall and fire taped. The door needs to have a self closing spring. Make sure to air seal it well so no gasoline fumes can get in the house.
    Any type of batt insulation should be fine - others can comment on this aspect better than I can.

  4. KYbill | | #4

    Thanks for the input on the tape, Tim.
    Likely wouldn't have thought of that.
    I'll check other related codes.
    Best, Bill

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