Track 2: Materials over Time: Points of Change

General Abstract

4 - Detailing in Transition: The Evolution of Architectural Terra Cotta Detailing Then and Now

Wednesday, September 26
8:30 AM - 10:00 AM
Location: HYATT-Grand EFG

When the National Terra Cotta Society (NTS) was created in 1910, one of the primary goals was to encourage the use of terra cotta in building construction. The society produced guide specifications and details in a folio that was first published in 1914. Prior to this time, architects and engineers relied on various articles and a few books that addressed the use of terra cotta as a construction and architectural material. Terra cotta manufacturers of the time also provided reference details to enable designers to understand the detailing, and to promote its use. Very little information was written or published following the Great Depression, which marked a rapid decline in the use and understanding of architectural terra cotta. Beginning in the late 1970s, the demand for terra cotta began to rise again, but much of the knowledge and experience with the material was lost. As a result of this hiatus, no standards were established and this essentially remains true today.

Many valuable lessons were learned from early 20th Century terra cotta buildings. As architectural terra cotta became more widely used and building heights continued to increase, the early terra cotta clad buildings began to age and the first generation of distress emerged. Improper maintenance of these early buildings, in combination with significant variations in the material properties of the terra cotta, resulted in the recognition that guidelines should be established. The body of knowledge represented in the 1914 edition of the NTS folio was generally limited to approximately twenty years of building construction. By the 1927 edition; however, almost thirty-five years of construction, along with maintenance repairs and costs had occurred. The thirteen additional years of experience pushed many of the early buildings through their critical initial maintenance cycles. Failures from improper applications, poor detailing, the inability to manage water infiltration appropriately, and a general misunderstanding of material properties resulted in significant modifications to the folio. A comparison of some of the details and specifications provide insight into the lessons learned. Many of the design and anchorage detailing changes between the 1914 and 1927 editions were based on in-service performance of terra cotta cladding.

Due to accelerated distress and recent failures of contemporary architectural terra cotta, the terra cotta industry is on the verge of another crisis. As such, it is necessary to revisit detailing, installation methodologies and material compositions. This presentation will compare and contrast the early detailing for architectural terra cotta including the 1914 edition of the National Terra Cotta Society publication with 1927 revisions, along with other relevant industry standards and provide an assessment of the lessons learned in the industry from recent failures and how that has translated into revised detailing, material production and installation.

Learning Objectives:

Rachel L. Will, P.E.

Senior Associate
Wiss, Janney, Elstner

Rachel Will, PE is a Senior Associate with Wiss, Janney Elsnter Associates in Chicago. She participates in various projects including facade evaluations, condition surveys, structural analyses, repair design, construction document preparation, and construction observation. Ms. Will’s expertise includes preservation and repair of historic masonry (terra cotta) building facades.

Rachel currently serves as the Past-President of the Western Great Lakes Chapter of the Association for Preservation Technology (APT) and a member of both the strategic planning committee and preservation engineering committee, along with member of the student design build competition subcommittee of APT.


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Edward Gerns, RA, LEED AP

Wiss, Janney, Elstner Associates, Inc.

Edward Gerns is Principal with the Chicago office of Wiss, Janney, Elstner Associates, Inc. and has extensive experience related to the investigation and repair of existing buildings. He has performed evaluations of historic masonry facades and overseen preparation of documents for the repair of numerous masonry buildings. The topic of architectural terra cotta been of interest to Mr. Gerns for numerous years.


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Chris Gembinski

Building Conservation Associates, Inc.


Chris is the Director of Technical Services for Building Conservation Associates, Inc., providing quality control and technical oversight for all BCA projects. Through his investigative work on hundreds of historic properties, he has developed extensive expertise in historic construction techniques and building systems, architectural materials, preservation design solutions, and construction management. Various aspects of his research and design have included masonry restoration, plaster restoration, historic finishes analysis, wood and metal window restoration design and stained-glass restoration. His work includes the design and management of conservation and preservation construction for: The Metropolitan Life Insurance Building, Grand Central Terminal, St. Patrick’s Cathedral, the Central Park Police Precinct, the Cathedral Church of St. John the Divine, and Trinity Chrch, Wall Street, as well as development ventures such as the Victoria Theater and Moynihan Station Redevelopments.


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4 - Detailing in Transition: The Evolution of Architectural Terra Cotta Detailing Then and Now

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