GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X 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

Exterior wall system with brick veneer

4NVCHfaoUq | Posted in Energy Efficiency and Durability on

We plan to use 8.5″ wide plates with a 2×6 wall on the exterior edge and a 2×4 wall on the interior edge, staggered to avoid contact with the 2×6 wall. We will spray 6-6.5″ open-cell insulation, use .5″ OSB sheathing and a final exterior layer of .5″ Tuff R, taped.

We are in Charlotte, so ambient moisture is as much of a concern as thermal. Any thoughts?

Also, is polyiso as effective as extruded polystyrene?

Thanks,
Tom

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.

Replies

  1. GBA Editor
    Martin Holladay | | #1

    Tom,
    Q. "Any thoughts?"

    A. Your wall assembly sounds fine to me.

    Q. "Is polyiso as effective as extruded polystyrene?"

    A. I'm not sure what type of effectiveness you are talking about. Foil-faced polyiso is an effective vapor barrier, which is a good idea in this case, because you want to stop inward solar vapor drive. If all you are thinking of installing is 1/2-inch rigid foam (as opposed to a thicker layer), then foil-faced polyiso is a more effective vapor barrier than XPS. When it comes to R-value, polyiso has a slightly higher R-value per inch than XPS.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |