4. Urban surfaces on buildings: A new paradigm for building facades
Historically, the prime and governing semantic message of a building has been indicated by the treatment of the outer surface of the building envelope, or its facade, and has alternated between exposing the important functions of the wall and con- humans lived in caves, dwellings had no outer surfaces—only an interior cavity. The eventual stacking of stones and other materials produced a new building element (walls), making it possible for humans to live in the open while being protected from the elements. These early stone walls expressed their load-bearing function. Later, walls were made smooth with the use of mud, wood, and other materials and became canvases for imagery, sculpting, and expression. The two- and three-dimensional ornamentation on these surfaces indicated the use, history, or importance of the structures behind them (Fig. 9). The addition of building services such as heating/cooling and plumbing contributed to the historic development of the building’s envelope; a development that can be seen in the integration of chimneys (Fig. 10) and in the location of radiators beneath windows. In the 20th century, interest in expressing honesty in the facade as either an extreme technological envelope (Fig. 11) or a materially invisible surface (Fig. 12) also became culturally popular. This position was then countered by a return to semantic messaging in the dematerialization of building envelopes by the intense use of lights, electronics, billboards, imagery, and text (Fig. 13), however, such extravagance is unsustainable and marginally irresponsible. The obvious question is: What comes next in the development of the building’s envelope?
