In the 21st century, it is not always easy to determine a building's construction type simply by walking around it and through it.
The "big box" stores from the late 20th century are usually easy to study. They are usually of Type II (noncombustible) construction, with exterior walls of insulated precast concrete wall panels (photo 1) or concrete masonry units (CMUs). The interiors can be either painted wall panels or CMUs or they may have metal furring strips and gypsum drywall board attached to the interior (photo 2). The ceiling is often the exposed steel bar joists and steel roof deck, although sometimes a suspended ceiling grid is installed with lay-in acoustical tiles.
