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

Insulation missing in space between first floor ceiling and second floor subfloor

mhunt11 | Posted in General Questions on

We are adding a second floor addition to our one story house. We’re living in it while it’s happening so most of the ceiling is staying intact as they add new floor system above. The contractor laid subfloor without insulating the exterior walls (bands) between the first floor ceiling and second floor subfloor.  We can cut back the subfloor in most areas but there’s a few places where it’s impossible. Is this problematic from a condensation point of view? Will the conditioned air in that space meet the exterior wall and create condensation and rot the exterior wall sheathing in those areas?

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
    NICK KEENAN | | #1

    You don't say what climate you're in. But if you're not in a mild climate it's problematic from a building science perspective. That area needs to be insulated and air sealed. Condensation probably isn't a problem. Rim joists can be problematic if they are insulated but not air sealed.

    Do you live in a place with code enforcement? The current International Residential Code would require that area to be insulated.

    1. mhunt11 | | #2

      I’m in zone 3. Charlotte NC

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |