Our house is a two story home. The person who built it decided to use the front steps as a closet for downstair. As a result the closet is really unuseable as it rains a lot in south carolina. It was not properly waterproofed and our first year we had a lot of mildew problems. we tried that paint that is suppose to stop that situation and we still have problems. please advice as to what can be done.Any ideas?