Many, if not most, chronic moisture problems in buildings are better understood by using building science. Many older buildings worked well as built, because they were constructed using specific materials and time-worn methods that were proven to work in that particular climate. 

As buildings age and are modified, the flow of heat, air and moisture are changed enough to overcome the ability of traditional construction to manage moisture flows. The changes often result in moisture damage and microbial growth from:

• Condensation on windows and doors that affects walls and floors underneath them;
•  Condensation hidden inside wall & floor cavities due to air leakage through building envelope;
• Wetting of exterior building materials (i.e., the 'skin') due to an improperly designed or constructed moisture-shedding layer on the exterior surface;
• Wetting of insulated wall cavities due to rain leakage through the roof, building exterior or from leaky plumbing lines.