Tools used to detect underlying structures, such as behind the surface of a wall, can include a first sensor, such as an electromagnetic sensor, configured to generate data indicative of the location of the underlying structure. Tools can include an indicator that provides an indication to a user based on the data. Tools can additionally or alternatively include an infrared imaging device for generating infrared image data indicative of the heat pattern of a scene. A display can display the generated infrared image data. Underlying structures may be visible in the heat pattern of the scene. The tool can indicate the presence of an underlying structure feature to an operator via one or both of the display and the indicator.