A tool for detecting a covered edge of a structural member through sealant material of a fillet seal includes an edge detection probe mounted to a fixture. The probe outputs an interrogation signal toward the covered edge and receives a return signal indicative of a location of the covered edge. The tool includes an electronic control unit (“ECU”) in communication with the edge detection probe and a display screen. The ECU is configured to generate, from the return signal, one or more XY coordinates indicative of the edge location, and to display the edge location on the display screen. Additionally, the tool includes a seal measurement device. In response to the edge location, the device measures a predetermined dimension of the fillet seal, including a thickness and/or a shape of the fillet seal. A method includes detecting the covered edge using the tool.