We did a 30x60 wood frame pole barn about 12 years ago. 20x13.25 2" foam filled overhead door. Used 1" closed cell foam insulation, walls & ceiling. I love it. We did several things, I read is the wrong way to do it, but if I had to do it over would do the same. No windows, No vents. No mice, very few bugs. Do have some very small spiders. Don't have to worry about freezing. Went through one spell, for 3 days, highs of 32 or below, lows 12/13. Did not freeze inside building, but was close. Almost stays dustless if keep doors closed. Did have to overcome woodpeckers breaking in by pecking out the insulation between roof ribs & sidewall panels. It also helps level out humidity.