Mold in the attic is caused by the intrusion of warm moist air due to factors such as elevated humidity in the living space, steam from cooking and showers; inadequate ventilation; leaking duct work and lack of solar drying. In most cases, excess moisture enters the attic through the ceiling, utility chases, electrical fixtures, and missing or improperly installed insulation and the attic entry way. This warm moist air is condenses on the colder roof structures during the fall, winter, and spring months. Without proper ventilation, excess moisture cannot be carried away, leaving the high possibility of mold growth in the attic.