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

Interior air barrier/vapor retarder

alcoprop | Posted in General Questions on

Quick run down. Climate zone 5A. Wall assembly: 2×6 studs, R23 rockwool, 7/16 zip, 3″ rockwool comfortboard, furring strips, siding. Question is do I need to use an interior vapor retarder other then my interior drywall? Should I use a product like Certainteed MemBrain as a secondary air barrier and vapor retarder? I am doing a blower door test hopefully this week and am shooting for 1ACH50 or better.  I have been doing a lot of research on here and when it comes to wall assemblies and vapor I still get confused but I am learning.

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. ERIC WHETZEL | | #1

    Shaun, we used almost the exact same wall assembly as yours.

    We chose to use Intello as a smart vapor retarder and as a secondary air barrier. The feedback I received from GBA suggested it wasn't necessary, although it is nice insurance. The MemBrain would obviously serve the same function.

    You can read about our wall assembly in detail here:

    https://kimchiandkraut.net/2020/01/22/completing-our-wall-assembly-self-build-passive-house/

    https://kimchiandkraut.net/2019/07/11/siding-1-of-2-continuous-insulation-with-a-rainscreen/

    1. alcoprop | | #2

      Thanks so much. Loved reading your articles! I agree with the added security of secondary air barrier so I believe I will go ahead and do it. Now just to find Intello or MemBrain in this crazy world we live in right now!

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |