Does a curtain wall have anything to do with actual curtains? Not necessarily. Today for Explainer, we define this common construction term.

In the context of architecture and design, the term curtain wall refers to a non-structural exterior cladding. In the early days of highrise construction, the structural load of a building was supported by thick load-bearing walls made of masonry. This would change in the late 19th and early 20th century, as timber-frame and load-bearing masonry construction was supplanted by more efficient media like structural steel and concrete. No longer bound by the constraints of load bearing exterior walls, architects were able to apply lighter materials such as glass as an exterior finish, allowing for greater design flexibility as well as penetration of natural light. 

Curtain wall system being installed on a Toronto construction project, image by Jack Landau

In essence, a curtain wall system refers to a non-load-bearing exterior skin of a building, generally glass. While the earliest implementations of non-structural curtain walls date back to the mid 19th century, like 16 Cook Street in Liverpool, the practice continued to evolve, and was most notably embraced by architects in Germany's interwar period. Examples of interwar period German curtain wall systems include the Kant-Garage in Berlin and the Bauhaus Dessau.

Kant-Garage, Berlin, image via Wikimedia Commons

In the decades since, curtain walls have evolved along with technology, growing from steel mullion and plate glass assemblies into modern systems that utilize materials such as extruded aluminum for mullions and require very little upkeep.

What are your favourite historic and modern implementations of curtain wall systems? Share your thoughts in the comment section provided below.