Well just as an example, around here concrete cellars were usually not insulated before. They were storage areas. In the 80s people started insulating them in

Well just as an example, around here concrete cellars were usually not insulated before. They were storage areas. In the 80s people started insulating them in the wrong way (on the inside), creating a condensation point between the insulation and concrete => mold. These days we have learned that cellars must be insulated on the outside (by digging up the garden) or somehow make sure humid indoor air dont make contact with concrete behind insulation. If you basically don't have plastic and insulation then mold is less of a problem, but you also need to spend a ton of energy keeping the house warm...