30x40 steel pole barn with wood frame and trusses, located in eastern Nebraska, 13' to the bottom of the trusses. I've been building 8' wall around shop so I can run electrical, put in workbench, and mezzanine. Insulating the walls with R-19 fiberglass batts, covered by 7/16th OSB. Did not include a vapor barrier in the walls.
I did use spray foam to seal gaps / seams at bottom of walls and at the wainscoting before building walls.
Down the road I would like to finish and insulate the walls up to trusses, then install ceiling at bottom of trusses, blown in insulation above that. Will likely heat the shop only...no AC plans at this time.
Been reading and considering vapor barriers and have seen different opinions.
Based on my climate "Zone" the local extension suggested putting a single vapor "retarder" on the inside of the walls, between heat source and insulation. They also said vapor barrier not necessary or required.
Other message boards are big on vapor barriers, suggesting they are needed.
Your thoughts on vapor barriers?