Track 2: Materials over Time: Points of Change

General Abstract

Conservation of Charles Follen McKim’s unique façade design at Pierpont Morgan’s Library

Tuesday, September 25
10:30 AM - 12:00 PM
Location: BNCC- 101BG

The Morgan Library and Museum is a complex of buildings in New York City, one of which is Pierpont Morgan’s original library designed by Charles McKim of McKim, Mead, and White. The 1906 McKim building, as it’s now known, is poised to undergo a comprehensive restoration of the exterior, and ICR is conducting a program of extensive research, investigation, field survey, and testing to develop the treatment plan.

This presentation will focus on the original use of thin sheet lead in lieu of mortar placed at the joints between the stone courses, survey of existing conditions, the inquiry into repair options, and the challenges that these lead joints present in developing a holistic conservation approach for the McKim building.

Built of Tennessee Pink, a thick-bedded crystalline limestone, the McKim Building is a magnificent example of Italian Renaissance-style, and no expense was spared in bringing the grand design to life. As a young man, McKim visited the Acropolis and was deeply moved by the elegance of the tight spaces between the dry laid stone units. Years later, McKim had the opportunity to present this idea to his client Morgan, who agreed and one of the most unique construction techniques in the United States commenced.

Sheet lead approximately 1/64“ thick was added to the external edge of the horizontal beds of each stone block. This building technique’s success relied on the precision and quality embedded in the design specifications for both the stone selection and the carving process, which was done locally.

While lead was not a new or innovative material at the time of this building’s construction in the early 1900s, its use in this context nearly unprecedented. Lead, used as a narrow joint material, has a significantly longer service life than mortar—yet a mortar joint can be easily raked and repointed when necessary. By contrast, the lead sheet presents greater challenges, since the large stone blocks are bearing on the lead and on one another.

Existing conditions at the lead joints consist of open joints (full loss of lead), heavily deteriorated lead, previous interventions, and staining of adjacent stone. ICR conducted comprehensive surveys to better understand the extent of these conditions present.

We believe staining to be a result of the lead weathering and its primary composition of lead carbonate and lead sulfate, which are generally insoluble compounds. This compelled targeted stain removal testing, in addition to general cleaning tests for the full stone façade.

We have begun in-situ repair trials with the aim of exploring repair techniques: for example, inserting new lead into some of the weathered or open joints where water infiltration is a concern. This presentation will evaluate the efficacy of these trials.

Learning Objectives:

Jennifer Schork

Senior Conservator
Integrated Conservation Resources, Inc.

Jennifer Schork is Senior Conservator with Integrated Conservation Resources, Inc. (ICR) where she designs, manages, and implements architectural conservation programs. A graduate of the Historic Preservation program of Columbia University, she has experience with building materials testing and analysis, hands-on treatment, and design-build project management. Ms. Schork is a Professional Associate of the American Institute for Conservation of Historic and Artistic Works (AIC) and former chair emeritus of the Architectural Specialty Group of AIC.

Presentation(s):

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Frances Gale

University of Texas at Austin

Frances Gale is an architectural conservator with a Master of Science in historic preservation from Columbia University and over thirty-year’s experience in preserving historic buildings and monuments. Fran was a Senior Lecturer and Conservation Scientist at the University of Texas at Austin School of Architecture for 11years. Other positions have included Architectural Conservator and Training Director for the National Park Service and Director of Technical Services for AMT Laboratories and Prosoco, Inc. Fran’s recent consulting projects include Union Terminal in Cincinnati, the University of Virginia Rotunda, Vanderbilt Mansion National Historic Site in New York, and the Matagorda Island Lighthouse in Texas. Fran was elected to the Association for Preservation Technology International College of Fellows in 2010 and became a Fellow of the American Institute for Conservation of Historic & Artistic Works in 2017.

Presentation(s):

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