"As Large as the Situation of the Columns Would Allow": Building Cladding and Plate Glass in the Chicago Skyscraper, 1885–1905

It so occurs that plate glass and steel construction are directly opposite in character, and yet both work toward the same end. The steel may be said to be the positive quantity and the glass the negative quantity. The steel is the solid—the glass the void. The glass can fill the space which the more positive material does not care to occupy.

—J.W. Yost (1896)1

The explosion in Chicago building construction during the economic boom of 1884–93 is often explained as an outgrowth of steel production, which allowed developers to exploit high rental values in the city's expanding real estate climate with multistory structures that used steel's inherent strength to increase tenant area. In The Autobiography of an Idea, for instance, Louis Sullivan declared that "the architects of Chicago welcomed the steel frame and did something with it," a claim that has been repeated in one form or another ever since.² Sullivan's claim is hardly worth arguing—without steel, the skyscraper would have been a structural impossibility. Yet the single innovation of steel framing does not fully account for the technical development of the skyscraper during the late nineteenth century. Even if we limit ourselves to those innovations with obvious architectural consequences—setting aside, for example, the hidden technologies of vertical circulation, foundations, and plumbing—there remain significant elements that not only accompanied the development of the metal frame, but were essential to the construction and functioning of the building. Among these, the most visible was the enclosure system, or "skin." In masonry construction, a building was supported by exterior and interior walls that, however they differed in appearance, were identical in purpose. The steel skeleton severed that traditional relationship of skin and structure. For the first time, a functionally independent exterior became a real possibility, and the resulting thin, light skins permitted—even encouraged—experiments with proportion, form, and fenestration.

Traditional explanations of early Chicago skyscrapers have focused on the steel frame, while recent scholarship has taken pains to relate structural considerations to cultural, economic, and social factors. Recognizing that late-nineteenth-century architects and builders responded to technologies other than steel, this article expands the relevant technical history by examining the development of the increasingly (and then decreasingly) transparent curtain wall. Like the steel construction facilitating its application, this enclosure system required manufacturing advances, function-driven performance standards, and innovative materials for its success. In the Chicago of 1885–96, the most important of these materials was plate glass, frequently paired with glazed terra cotta.³ This combination contributed to a new type of building exterior, one that allowed architects and developers to more fully exploit the attenuated proportions and lighter weight of the steel frame.

Daylighting: Glass as an Alternative to Masonry

Two conditions that led Chicago architects and engineers to think beyond traditional masonry construction were the compressibility of the native clay soil and the need for natural light. With thick, load-bearing walls, not only did each floor increase the load on the foundation, but the weight of these floors had to be redirected around door and window openings in exterior walls—a structural requirement that necessarily limited these important light-gathering apertures at a time when electric lighting was expensive and inefficient.⁴ The advent of metal framing was significant here for two reasons: not only did it weigh less heavily on compactible soil, it allowed a significant increase in aperture width and, thus, in the potential amount of daylight entering the building.⁵

FIG 1.

An example of emerging skeletal construction: The Rookery, LaSalle and Adams streets, Chicago (Burnham and Root, 1888). Iron-reinforced brick piers enabled larger apertures, but the overall proportions of the building's skin remained largely solid. (Source: author's collection.)

This transformation was not instantaneous (fig. 1). Despite its tentative exploration of iron and steel framing, even William Le Baron Jenney's heralded Home Insurance Building (1885) recalled its bearing-wall predecessors in...