Depending on the construction, roofing details that may be viewable with an infrared camera include the placement of joist, insulation, fasteners, blocking, and others.

Fastener patterns due to the minor amount of heat
transmitted thru the fasteners.
Depending on the construction, wall details that may be viewable with an infrared camera include the placement of studs, insulation, fasteners, blocking, piping, reinforcement, and others.

Locate or confirm the placement of reinforcing in masonry
walls.

Studs and bracing in wood frame construction.