There are many reasons why building inspections are conducted. Governmental agencies use building inspections to check compliance with building plans and with local codes and ordinances. Building inspections are a routine part of buying and selling homes, helping prospective sellers identify problems they are legally responsible for and helping buyers know what they are getting into.
Property managers also use inspections for preventative maintenance. Building inspectors are called upon in the process of construction itself, to help the builders with structural design issues, storm water handling issues, and electrical concerns. As buildings age and settle, or weather storms, or undergo renovation or construction of additions, building inspectors are often called in to address safety concerns. Inspectors usually check the structure of the buildings as a whole, the foundation, the roof, the electrical systems, the plumbing systems, the interiors of walls, the attic, insulation, air conditioning, appliances, and pools.
It is a completely non-invasive procedure: to determine if there are voids in the external insulation of a building, the technician may not even need to enter the building.
Rob Haller, Drone Navigator