GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Frame partition walls AFTER strapping ceiling

entomodonata | Posted in General Questions on

I’m remodeling the upstairs of a 1.5 story Cape. I’m installing continuous interior foil faced polyiso from the 1st floor top plate, all the way up the rafters, across the collar ties (ceiling joists) and back down the other side, in addition to up the two gable walls. It will all be seam taped. I’ll then be leveling the ceiling with 2×3 strapping, while also creating a cavity to run electrical with minimal disturbance to the polyiso air seal. 

Does anyone see any issue with me framing my interior partition walls AFTER installing the strapping? This would allow for longer runs of strapping, a continuous cavity for electrical from room to room, and because of my order of operations, make my polyiso install easier.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. Expert Member
    DCContrarian | | #1

    In New England it's normal to strap the ceiling with 1x3. The space is used to run wiring and even sometimes 1/2" plumbing, and even though it's not technically to code it's accepted practice. I have a feeling that it's lacking when it comes to fireblocking as well but I can't think of a specific reason.

    While normally the strapping is added after the partitions are in place, when adding a partition in a renovation it's entirely normal to put the partition under the existing strapping.

  2. Expert Member
    Malcolm Taylor | | #2

    It sounds like a good idea, especially as the strapping is 2"x.

  3. entomodonata | | #3

    Thank you for the confirmation, DC and Malcom.

    I might keep the crazy ideas going and hang all my sloped and flat ceiling drywall before framing interior walls as well. Less joints right?

    I’ll just need some long screws to get through the 2x, ceiling drywall, strapping, 1.5” foam, and then into the rafters/joists for my top plates on the partition walls. But maybe not? Getting into the strapping alone, given its 2x, might be a strong enough connection.

    Time to build a mock-up...

    1. Jason S. | | #4

      The main advantage of the strapping is creating an electrical chase inside of the air barrier. If you hang drywall before electrical rough in, that advantage is lost or at least compromised -- fishing wire may still work but I imagine it's slower and tedious.

      Make sure to space the strapping enough for tipping interior partitions into place. Or strap 2x4 where they will eventually align and frame them 1 1/2" shorter.

      1. Charlie Sullivan | | #5

        Trying to think through the sequencing here I'm not sure I'm thinking straight, but it might be possible to do a partial electrical rough in without walls, then add the ceiling, then the walls, then finish the electrical rough in. That might complicate inspection, as well as requiring more visits by the electrician, so it's not easy.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |