Your question on foam and condensation: I've gone over this several times here, but there are always new members coming on , so here goes.
Condensation occurs when the air inside hits a surface that is below the dewpoint of that air. So you have a lot of humidity inside and no insulation and metal siding (the easy example of an open pole barn). The metal is going to be at the outside temp pretty quickly. As it cools off at night, the metal temp will drop below the dewpoint of the air inside, and moisture will condense on the inside, and rain down on your stuff. So you add fiberglass, right? Well that helps limit the heat loss, but it does not stop moisture, so the humidity goes right through it to the metal, condenses, and then makes your insulation wet. No it does not insulate, starts to rot stuff, attracts bugs, etc. So you go to OPEN CELL spray foam as foam is better, right? Well the insulation per inch is high than fiberglass, but it is still moisture permeable, so you have the same general problem, though now it is a wet sponge on your walls and ceiling. OK, one more time. Closed cell foam - now this is an insulation with both thermal and vapor stopping capabilities. You do this, and all is well, right? Well not so fast. A lot depends on how much you put on, and that depends on your climate zone. if you don't put on enough, then it does not keep that metal siding cool enough vs the interior warm temps, so you can still get condensation. Here is one table from the code. Do a quick search to find more details on this:
R-5 foam for Climate Zones 1-3,
R-10 for Climate Zone 4C,
R-15 for Climate Zones 4A and 4B,
R-20 for Climate Zone 5,
R-25 for Climate Zone 6,
R-30 for Climate Zone 7, and
R-35 for Climate Zone 8.
It's all about the dewpoint and the surface temp of the exterior sheathing/siding. Pay attention to that, and you should be fine. Pole buildings are not the easiest to insulate, so it will be harder to do, but can be done if you are careful.
Dave
