I can share my two experiences with mildew. I was building my first little house and I had mildew grow on my untreated ceiling joists. Another summer house I worked on had mildew develop in the springtime after being unheated one winter. Both cases were related to condensation on the cold building surfaces during sudden warm, humid weather. So, I would say to add heat to the ventilation and water penatration equation.
Just how many bad molds are there?
