I have a sixty year old house that has a 7' high basement on one side, and a 3' high crawlspace on the other. in between is a poured concrete wall. This basement has never been (properly) finished. In particular, the wall between basement and (unheated) crawlspace has never been finished. I want to frame and drywall this wall but don't know if I need a vapour barrier or insulation. Will condensation occur the same as a true exterior wall, or would the temperature in the crawlspace be constant enough to prevent this? For my exterior walls I am using rigid polystyrene/tape/studs/drywall.