Performance
In rainscreen applications, terra cotta has a natural capacity for cooling. In fact, it has been used as protection against hot climates in many cultures and civilizations throughout history. In cold weather, its high thermal inertia can also help contain heat loss when it is installed as part of a ventilated rainscreen system. The back ventilation assists in maintaining a dry cavity and negates the buildup of hot air in the cavity.
Terra cotta is also known for reducing sound transmission. During the manufacturing process, terra cotta becomes denser as the temperature increases and silicates melt. In many designs, the addition of a glaze to the exterior facing surface creates a smooth, reflective plane. These combined properties provide sound deflection, which helps reduce the intrusion of outdoor noise into interior spaces. Terra cotta tiles with more natural or deliberately textured surfaces also disperse sound waves, and those panels produced for exterior cladding are designed with a hollow air chamber in each panel or tile to further suspend the transmission of sound.
Resistances
Terra cotta has been recognized as an important material in fireproof commercial construction in the United States for more than a century, as its clay-based composition renders it naturally fireproof. These properties, along with the denseness of the clay, result in minimal thermal transmission, making terra cotta virtually impervious to the effects of ultraviolet (UV) light. This in turn provides natural resistance to both heat and light—elements commonly causing deterioration in other façade materials. Modern glazing and firing techniques can also make terra cotta resistant to water, eliminating the damaging effects of water infiltration in addition to the deterioration experienced in most cladding materials subjected to heat and frost cycles.
History and use of terra cotta in Chicago
Terra cotta’s fireproof properties led to its incorporation in an important building trend beginning in the United States nearly 100 years ago. Chicago is credited as the origin point of many of the stylistic and technical advances associated with tall buildings—elements of the modern skyscraper. In the years following the 1871 Chicago fire, design and construction teams developed techniques to build safer structures with greater fire resistance. In 1873, architect John M. Van Osdel designed the Kendall Building, the first fireproofed building in the United States. The structure included terra cotta tiles to protect its structural elements. Such fireproofing properties make it an appealing construction material to this day. (From the Infrastructure Protection and Disaster Management Division of the Advanced and High-Performance Materials Program’s winter 2011 Journal of Advanced and High-Performance Materials, a publication of the National Institute of Building Sciences (NIBS) Advanced Materials Council.)
In the 20th century, the Windy City was a hotbed of architectural talent, with architects of the Chicago School venturing into new construction techniques such as the design of the city’s first skyscraper. In 1920, Graham, Anderson, Probst & White designed the Wrigley Building to serve as headquarters for the chewing gum manufacturer. Completed in 1921 and 1924 respectively, the 130-m (425-ft) south tower and 137-m (450-ft) north tower took inspiration from the Giralda tower of the Seville Cathedral in Andalusia, Spain. Both towers of the building façade comprise more than 250,000 glazed white terra cotta tiles. Almost a century later, these tiles maintain their attractive appearance.
Another important feature of terra cotta is its versatility, which allows manufacturers to customize tiles and panels to create unique shapes, colors, textures, and glazes for expressive and individual design solutions. Terra cotta’s material adaptability also makes it a suitable choice for repairing or adding to structures designed decades ago. Custom-designed terra cotta can reference Beaux Arts aesthetics, provide continuity with a historic district, integrate into regional construction and design techniques, or support modern sleek and minimal design statements.
A project in progress at 111 West 57th Street in New York City demonstrates the versatile design possibilities of custom terra cotta. Inspired by the terra cotta façade of Manhattan’s Woolworth Building, this unique structure has the smallest footprint of any skyscraper worldwide. Designed by SHoP Architects, it tops out at more than 426 m (1400 ft), and will be among the tallest towers in the city. The structure represents a commitment to the quality of craft, history, and thinking behind New York City’s classic skyscrapers.
Intended to be a reinvention of the landmark Steinway building designed in 1925 by Warren & Wetmore, this building is being restored and refurbished. Its terra cotta façades, combined with bronze filigree, are meant to bring back the quality, materiality, and details of historic New York towers while taking advantage of the latest technology to push the limits of engineering and fabrication. The tower’s form multiplies the setback to present a feathered profile, rather than a stepped profile. As with the Wrigley Building, this structure’s façade will be constructed of white, glazed terra cotta tiles.
