curtain wall

In a building, an external, lightweight, non-loadbearing wall (either glazing or cladding) that is hung from a metal frame rather than built up from the ground like a brick wall; the framework it shields is usually of concrete or steel. Curtain walls are typically used in high-rise blocks, one of the earliest examples being the Reliance Building in Chicago (1890-94) by Daniel Burnham and John Wellborn Root. In medieval architecture, the term refers to the outer wall of a castle.

In the early 20th century, the curtain wall was developed in two buildings by Walter Gropius: the Model Factory, Deutsche Werkbund Exhibition, Cologne (1914), and the Bauhaus, Dessau (1925-26). Since World War II its use has spread dramatically, initially in the USA with iconic buildings such as the Lever House, New York (1952), by Skidmore, Owings & Merrill, and the Seagram building, New York (1956-59), by Mies van der Rohe.