Warm moist air on a cold surface equals dew point, or condensation. The insulation keeps the heat in, but it also keeps the cool in as well. Insulating and vapour barriering the walls and ceiling will keep the walls and roof from condensing (thermal break). Unfortunately when you inject humid air in the summer when the inside if the shop is still relatively cool, you'll still get condensation on cold metal, and concrete (relatively speaking of coarse). Just think of your toilet tank in the summer. I used spray foam in my shop. It works great but it is expensive. And....I keep the door closed when the humidity goes up outside. Good luck.
