Hi Aida, trying to follow, but it's my lack of experience with what you are doing. In addition to the problem with two vapor barriers is the question of which direction that area will be able to dry.
If the inside of the box will be drywalled and that air space will be circulated with the living space then I tend to think no vapor barrier. But, looking from the inside out, any humidity in the air that migrates through the drywall and makes it to the colder outside might not be good.
Does the 1.5" wood extend down to a warmer area where moisture might take the longer path to dry in that direction. If so, then the VB under the drywall sounds the best.
Thoughts?
Bud
If the inside of the box will be drywalled and that air space will be circulated with the living space then I tend to think no vapor barrier. But, looking from the inside out, any humidity in the air that migrates through the drywall and makes it to the colder outside might not be good.
Does the 1.5" wood extend down to a warmer area where moisture might take the longer path to dry in that direction. If so, then the VB under the drywall sounds the best.
Thoughts?
Bud