Infrared imaging is a valuable tool for nondestructive evaluation of thermal properties in masonry walls. For example, the technique determines whether reinforced cells are properly grouted, whether a wall cavity is filled or empty, and where moisture may be entering masonry walls. This technology allows the user to scan large areas of a structure quickly and in a continuous manner.

All objects with a temperature above absolute zero (-459º F) emit some thermal radiation. Infrared (IR) thermography measures this radiation and detects voids or discontinuities by sensing the thermal affects these types of defects produce.

When thermal energy passes through a masonry wall, any break in the conduction path results in a different surface temperature over the thermal break. Areas with solid construction, such as grouted cells in a masonry wall, have a different temperature than voided cells. Today's portable infrared cameras detect surface temperature differences as low as 0.18º F.