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

Closed-cell insulation

steelbook | Posted in General Questions on

We are putting close cell insulation in an all metal shop. 1800 sq ft.
What should we watch for ? How thick should it be? We’re in Alabama and it goes get pretty warm. Building has no shade .

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. GBA Editor
    Martin Holladay | | #1

    Assuming that this building is subject to building codes, you should check with your local code authority. Most of Alabama is in Climate Zone 3, although the southern part of the state is in Climate Zone 2.

    In Climate Zone 3, the minimum R-value for roofs is R-38 (about 6 inches of closed-cell spray foam), while the minimum R-value for walls is R-20 (a little more than 3 inches of closed-cell spray foam).

  2. charlie_sullivan | | #2

    Ordinary closed cell spray foam has an unreasonably high, outsized global warming impact. Fortunately, you can now specify "HFO" blown foam to avoid this impact.

  3. Expert Member
    Dana Dorsett | | #3

    Is it just the roofing & wall cladding that is metal, or are all the structural elements metal too?

    If it has steel studs thermally bridging the closed cell foam any amount or type of closed cell foam is a waste.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |