When it comes to housing typologies, the term duplex –lends itself to multiple interpretations, often leading to ambiguous applications and uses. The definition of the concept depends primarily on the country or region in which it is used, generally allowing for two main interpretations. First, a duplex can refer to a two-story housing unit with levels connected by an internal staircase. This definition usually applies to apartments and residences in countries like Spain or Canada, which are typically found in urban centers. Alternatively, a duplex can describe a specific type of project where two homes are joined side-by-side, each having its own individual entrance but sharing a central wall. Generally, the design of these houses is defined by an intentional axial symmetry, functioning as twin homes with the same features and floor plan layout. This type of duplex housing is particularly common in Argentina, Bolivia, the United Kingdom, Australia, and parts of the United States.
Etymologically, the word comes from the Latin adjective duplex, which simply means “double.” Outside the field of architecture, it is typically used to describe things that manifest in pairs—that is, something that presents the same thing twice or holds twice a certain amount. Therefore, it makes sense that the term can refer to both a project of two semi-detached or “twin” houses, as well as a single housing unit spanning two levels.
