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Best place to “double up” air sealing on a Perfect Wall, in your opinion?

qofmiwok | Posted in Energy Efficiency and Durability on

I’m aiming for a very tight house.  My approach follows Lstiburek’s Perfect Wall where the air sealing is a SA WRB (Blueskin) which starts at the foundation waterproofing, goes up the wall sheathing, over the top sheathing, and back down.  A sloped cold roof will be built on top of this (vented but not accessible).  2″ Rockwool and a rainscreen goes over the WRB. 

Knowing that there are areas of connection where leakage typically occurs, which would you focus on “double sealing” with tapes or sealants, or maybe I should say “triple sealing” meaning upgrading an already double barrier to a higher quality one.  For example, will most sill seal/gaskets do the job under the WRB, or is that worth upgrading to a more expensive, higher tech sill seal/gasket?  Which seams should be especially well sealed or taped before  applying the WRB?  Etc.  

I’ve read that the bottom and the top are most important, to combat stack effect, and of course am focused on all the penetrations.  Just looking for real world advice as we begin the actual build.

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  1. kyle_r | | #1

    I would check out this blog by Eric Whetzel ( He did a lot of redundant air sealing and has been featured on GBA.

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