My wife and I bought a 1960s vintage house in N Minnesota.  We had problem with the walls sweating in a couple places last season and then molding.  We have taken care of the unvented heat source problem and we’re using electric baseboard.  To help add insulation, I added 3/4″ pink rigid foam board over the existing drywall on the two exterior walls (glued and screwed) and in the next day or two will cover that with new drywall.  Do I need to add another vapor barrier over this new foam board prior to covering it with drywall.  There was a plastic vapor barrier used over the original fiberglass batts under the original drywall.  Just as an added related question, there are thin poly sheets covering the pink foam from the manufacturer.  It says it is for protection of the foam, but does it act as a vapor barrier too?

Jerry Johnson