Pre-engineered structure commonly referred to as the K-Span. Built in place, the corrugated sections are extruded on site with a roll forming machine. Interlocking sections form the roof structure,which, when placed on concrete foundation walls at the base provide raintite protection for equipment and personnel. Ends are enclosed, doors added, and, with HVAC units attached, these are often built out for office space, gyms, mechanic shops and anything else you can think of. The successor to the quonsot hut, a K Span is quick and cheap to erect, erected by the thousands these are often put up by Seabees, the Navy's builder/fighters.