Mold on insulation...I think?
I have an unfinished basement that I am in the process of finishing myself. I have a walk-out basement and live in Minnesota. In our frequently very-humid summers (I know...it gets much more humid in other climates), my basement is nice and cool. On my exterior exposed 2X6 basement walls, here is the layering of materials as far as I can see(and maybe this is most typical):
Exterior OSB sheathing
2@6 Walls with fiberglass insulation
On those summer days when it is very humid outside, I see moisture on the inside (insulation side) of the vapor barrier. Is that to be expected? That is in fact, the vapor barrier’s job, correct? Should I be concerned? The fiberglass insulation appears to have mold spot, but I am not sure if it is mold. I was told that mold really only occurs when you have constant moisture that does not dry up. Well, we have some instances where we have up to a week of humid weather. That might constitute constant moisture. I have talked to neighbors that have similar houses/basements and they don't get moisture like I do on their vapor barrier/insulation.
Would you recommend that I remove and discard all the insulation, install vapor barrier sealed tightly against the sheathing and then install new insulation before I finish the basement completely?