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Community and Q&A

Top plate sealing? (ADA)

user-1064942 | Posted in Energy Efficiency and Durability on

We plan on using Conservation Technology EPDM gaskets between the slab and (bottom) sill plate. And then some form of gaskets to create the airtight drywall approach (either the ones from conservation technolgy or Denarco).

What I am still a little unclear about is what if any seal is needed at the top plate(s)? The house will have a double 2×6 top plate. I have looked at a few different diagrams about ADA and weather sealing and for some reason I am still confused.

I found this diagram from an older post by John Brooks (hope you don’t mind me using it):

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  1. GBA Editor
    Martin Holladay | | #1

    Yes, you need a gasket or caulk between the drywall and the top plate. As I wrote in my article on the topic, "Use a continuous bead of caulk or drywall gaskets along the bottom plates and top plates of exterior walls, along the top plates of partition walls under insulated ceilings, and around the perimeter of all rough openings."

    Here's a link to the article: Airtight Drywall.

  2. user-1064942 | | #2

    Thanks Martin. Is there anything needed between the top plates, i.e., between the sandwiched 2x6s?

    Is the purpose of the gasket along the top plate (behind the drywall) to keep the air from the attic, in the attic?

    It would seem that if we seal the drywall along the bottom plates, around all perimiter rough openings, and electricl boxes, then air from the interior of the home couldnt leave the house through the area of the top plate as there doesnt apear to be a path to get there? I am sure I am missing something obvious.


  3. GBA Editor
    Martin Holladay | | #3

    To do a conscientious job of air sealing, it's a good idea to caulk the joint between doubled framing members (including double top plates) for the drywall is hung.

    The gasket at the top plate serves several purposes. On exterior walls, it creates an air seal at the top of stud bays to improve the performance of fibrous insulation installed between the studs. It prevents exterior air that may have entered the stud bays from leaking out the top of the stud bays.

    The gasket at the top plate of partition walls prevents conditioned interior air that enters the partitions through electrical outlets from escaping into the attic.

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