Building design, construction, operation, and maintenance can each contribute to building faults and failures that result in mold impaction of installed building materials. As complex and interrelated as various aspects of building performance can be, the common denominator in all cases of mold-impaction is the availability of water. Humidity and condensation can promote mold growth. Preventing water incursion or reducing dampness in the indoor environment is the key to preventing mold growth in buildings. Sometimes, attention to the construction sequence, selection of building materials, and rapid response to water incursions when they occur can prevent or limit mold growth in buildings. Several significant litigations centering on design and construction defects of governmental buildings that caused mold impaction, and subsequent claims of adverse health effects among building occupants, have recently been concluded. In each case, unique problems associated with curtain wall design and installation, building HVAC system performance, and other building defects resulted in dramatic mold growth within the buildings. In all cases, awareness of how moisture and water loads are managed in buildings and action to resolve any related problem conditions both during and after construction could have prevented or limited building damage and resultant liability.