Roof leaks are typically discovered by direct observation. If the roof sheathing is not visible from below, such as in an attic, the wallboard or ceiling covering must first be removed. This removal is necessary in order to “visualize” the intrusion point at the underside of the roof sheathing. Before the ceiling is removed, all contents must be removed from the affected area. The floor is then protected from falling debris, and the ceiling is removed, possibly requiring a scaffold system. Infrared thermography is an invaluable tool in the discovery of roof leak intrusion source without the need to remove the ceiling or contents of the room. The thermal properties of water are unique, allowing water to be observed on the surface of building material or even within the building material being examined. When water evaporates on the surface of building materials, it cools. If the building material is at a different temperature, the water’s thermal difference may be detected by conductance through the building material.