The separation of exterior tiles from buildings diminishes the visual appeal of cities and can injure pedestrians when they are struck by falling tiles. Therefore, tiles should be inspected periodically. However, completion of the inspection process has hurdles, including high cost and the need for qualified human inspectors. This study describes a non-destructive inspection method for detecting voids that match those seen in tile separation in a concrete specimen using electromagnetic waves, specifically microwaves. The method can be performed using devices that are simpler, smaller, and easier to use than those required by conventional methods. In addition, this method can be used to measure the adhesion strength of tiles.