Courtesy Arketex via BTHL

This post is part of a monthly series that explores the historical applications of building materials and systems through resources from the Building Technology Heritage Library (BTHL), an online collection of AEC catalogs, brochures, trade publications, and more. The BTHL is a project of the Association for Preservation Technology, an international building preservation organization. Read more about the archive here.

What do the Flat Iron Building in New York, the Wrigley Building in Chicago, and the Artic Club Building in Seattle—three of the most iconic buildings of the early 20th century—have in common? Each features intricate terra-cotta cladding systems.

Architectural terra-cotta is an ancient form of masonry that is still used extensively today. Terra-cotta literally means “fired earth,” a nod to the process of turning clay into a durable product used in pottery, floor tiles, and roofing. And the ability of glazed terra-cotta tiles, hung on a steel frame, to imitate expansive masonry walls made the material a popular choice for architectural expression and durability during the early 1900s. The individual but repetitive nature of the fabrication process made terra-cotta construction much more economical than carved stone for elaborate building exteriors.

Also installed in fireproof wall and ceiling systems, glazed terra-cotta tiles became extremely popular on the exteriors and interiors of schools, hospitals, and other spaces requiring special hygienic conditions and often eliminated the need for additional plaster or stucco finishes.

While architectural terra-cotta largely disappeared by the mid-20th century, there is now an active market for terra-cotta restoration products to maintain the legacy of landmark terra-cotta buildings. The BTHL has extensive documentation of the historical building product and its architectural use through the 20th century.

The Openuxazyvvavydrfdxb Hearth: A Catalogue of Designs of Brick and Terra Cotta Fireplace Mantels, Fiske, Homes & Co., Boston, 1897
Small ornamental pieces integrated into brick construction—such as fireplace mantels and chimney pots—were among the earliest uses of terra-cotta.

Fireproof Building Materials, Henry Maurer & Son, New York, c. 1889
Terra-cotta tile with an integrated steel frame structure as a fireproofing system was a late 19th-century innovation. This is one of the earliest such catalogs in the BTHL.

Fireproof Houses of Natco Hallow Tile and How to Build Them, National Fire Proofing Co., Pittsburgh, 1910
The Natco brand of terra-cotta tile as a fireproofing material was one of the best-known brands in America. This catalog lists some advertised benefits of the material including reduced maintenance and repairs; moisture, sound, and vermin proofing; and temperature control. There are more than two dozen Natco publications in the BTHL covering the everything from garages to high-rises.

Fireproof Construction in Terra Cotta Hollow Tile, Dominion Fire Proofing Co., Winnepeg, Canada, 1912
Dominion outlines the advantages of its tiles specific to the weather conditions in Canada claiming its terra-cotta is lighter that other materials such as concrete, provides insulation and fireproofing, enables quick construction, and is amenable to alterations. In addition to material specs, readers can also peruse examples of steel-frame building construction with integrated terra-cotta tile fireproofing.

Natco Hollow Tile Fireproofing, National Fire Proofing Co., Pittsburgh, 1915
This publication is a regional edition of the Natco brand of tiles that specialized in terra-cotta for high-rise steel construction. In addition to details of standard terra-cotta units, this volume contains structural tables for terra-cotta tile structural arches.

Common Brickwork Architectural Terra Cotta, International Textbook Co., Scranton, Pa., 1920
As a technical volume rather than a trade catalog, this two-part publication contains a detailed overview of the advantages, uses, and design of architectural terra-cotta.

Handbook of Hollow Building Tile Construction, Hollow Building Tile Association, Chicago, 1922
Trade association technical publications are often featured in the BTHL because they provide extensive details on industry-approved construction practices.

Store-Front in Architectural Terra Cotta, New Jersey Terra Cotta Co., New York, 1924
The use of architectural terra-cotta for urban commercial buildings was popular during the first three decades of the 20th century. This catalog advertises the material in storefronts, as well as in terra-cotta and masonry façades for buildings up to 15 stories tall.

Midland Terra Cotta, Midland Terra Cotta Co., Chicago, 1925
Primarily a visual reference guide for readers, this catalog depicts architectural terra-cotta elements as both individual details and integrated façade components.

Architectural Terra Cotta and Wall Ashlar, Federal Standard Terra Cotta Corp., New York, 1938
Architectural terra-cotta evolved with the stylistic changes in America in the 1930s. Traditional ornamental styles gave way to more geometric shapes rather than symbolic motifs. Flat terra-cotta panels with contrasting graphic designs allowed a traditional material to compete with then-new materials such as structural glass and porcelain enamel.

Handbook of Standardized Glazed Brick and Tile, Glazed Brick and Tile Institute, Washington D.C.,1938
Glazed architectural tile represents the third wave of architectural terra-cotta in North America. It could be used as both an exterior and interior finish material.

Arketex Ceramic Structural Glazed Tile, Arketex Ceramics Corp., Brazil, Ind., 1957
This catalog features a colorful array of finishes for glazed terra-cotta tile, emphasizing its use as an interior wall system.