My parents just purchased a house in Oklahoma. They have a concrete storm shelter that is attached to their house. It is a shelter built in the 1960 to 70's. It has 3 windows and about three feet of it is above the ground. With the colder weather we have noticed quite a lot of condensation where the shelter is exposed to the elements. What can be done to prevent this. My father was planning on bricking the exterior wall to cover the windows to secure it from tornados. If he does that should he use a vapor barrior or some type of insulation between the shelter and the brick wall, and what should we do about the top. Any suggestions?