A couple of months earlier, I inquired about my wall assembly (Vapor barrier on interior with stiff foam exterior– GreenBuildingAdvisor)
TLDR: Wall assembly is: Steel siding– Home wrap- 1 ″ outside constant insulation (taped and glued)– 6 ″ steel girts with 6 ″ R19 in the cavity, plywood/drywall covering the wall. The agreement was proceed with the cavity but do not do anything to slow down the wall drying to the inside of the structure.
Concern is this: The structure has bonded steel truss columns every 13-14 ft. Each truss a 3/4 ″ space in the middle that goes from the floor (see attached image). As you can see, I can not cover this area with drywall. My very first instinct was to just push 1 ″ backer rod in the gap. But then I got to believing that I must probably do a better job of air sealing. Even more yet, I began to wonder, should I really be sticking some type of vapor retarder at each of these broad spaces to promote the way drying (to the interior) simpler? I am probably overthinking, but if a vapor barrier provides some significant advantage, I wish to go that route.
I have a few choices:
Excellent things foam the area and paint
Glue a piece of 1/2 ″ foam to the backside (cavity side; it will compress the fiberglass insulation a little)
Glue a piece of kraft paper from the behind (cavity side)
Usage backer rod and some type of sealant (foam, caulking, etc)
Use tape from the wall cavity side (haven’t found lots of tapes that are vapor permeable)
Are any of these alternatives most preferrable or does it actually make a difference as long as I get a good air seal?