People
John J. Walsh
President/ Senior Petrographer
John Walsh is the founder and president of Highbridge Materials Consulting. He holds a Master’s Degree from Columbia University as a National Science Foundation Graduate Research Fellow and a B.S. in Geology with Honors from Queens College, CUNY. John has extensive experience in the application of petrographic and chemical techniques to the examination of a wide variety of construction materials and practices. Additionally, he is a recognized expert in the application of these techniques to investigations related to historical concrete and masonry. In 2023, John was awarded the Harley J. McKee award by the Association for Preservation Technology International, the highest honor bestowed by the organization for career contributions to the field of preservation technology.
Heather Hartshorn
Vice President/ Senior Chemist
Heather Hartshorn is the vice president of Highbridge. She also serves as the firm’s senior chemist. Heather has Master’s Degree in Historic Preservation from Columbia University, where she also currently teaches a course on Concrete, Cast Stone, and Mortar. Prior to her graduate work, Heather earned a Bachelor’s Degree in Chemistry and Art History from Trinity University. Heather is actively involved in the research of novel modifications of chemical methods to better solve problems in historic cement and lime mortar analysis. She also exceeds the requirements for petrographers specified in ASTM. Heather is actively involved in ASTM and serves on the board of the Northeast Chapter of the Association for Preservation Technology (APTNE).
George Wheeler, PhD
Senior Scientific Consultant
Dr. George Wheeler serves as a part-time Senior Scientific Consultant. George specializes in the examination, evaluation, analysis, and conservation of masonry materials with an emphasis on stone. He is widely published and is a frequent presenter at conferences in preservation, conservation, and conservation science. Additionally, he was a Research Scholar in the Department of Scientific Research at the Metropolitan Museum of Art, has taught at New York University’s Conservation Center since 1983, and was the Director of Conservation at the Historic Preservation Program at Columbia University from 2004 to 2017. His monograph, Alkoxysilanes and the Consolidation of Stone was published by the J. P. Getty Trust in 2005. George was also awarded a Rome Prize in 1997 and is a fellow of the American Institute for Conservation and the International Institute for Conservation.
Michael Pattie
Senior Technician
Michael Pattie is the lead technician at Highbridge. Mike has over twenty years experience in technical support including tenures in product testing, field testing, and construction materials laboratory testing. At Highbridge, he is responsible for all aspects of sample handling and preparation. His talent and attention to detail ensures that delicate or rare samples are properly handled.