Landmarks are more than grand spaces and historic finishes. While infrequently seen – except mid-renovation – seemingly mundane archaic structural systems, including the once commonly specified floor assemblies that incorporated terra cotta and cinder concrete, are an important part of the history of technology. But what sometimes gets lost in that story is the narrative that tells of the determination and inventiveness of the people who developed the systems and the continuing value of the approach they took to demonstrating the merit of what they produced. 

 In his lecture, Derek Trelstad of Silman Structural Engineers will examine this often overlooked – but essential part of any landmark, the floor. Mr. Trelstad joined Silman in 2006 and was named an Associate with the firm in 2007. His professional experience includes historic preservation and renovation projects.  Notable projects include: restoration and alterations to accommodate systems upgrades at St. Patrick’s Cathedral, New York; ongoing work at the Cathedral Church of St. John the Divine; documentation of conditions and design of repairs at Cincinnati Museum Center; and existing conditions assessment and preservation plan for Montrose Placer Mining Company Hanging Flume, Colorado.

Mr. Trelstad is a graduate of Columbia University (M.S., Historic Preservation) and of the University of Vermont (B.S., Mechanical Engineering). He has a Certificate in Stone Preservation from the International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM) / University of Pennsylvania and a Diploma in Preservation Carpentry from the North Bennet Street School.

 20 WEST 44^th Street  (BETWEEN 5^TH AND 6^th AVENUES), New York City

$15 General Admission; $10 General Society Members and New York Landmark Conservancy Members and Senior Citizens;  $5 Students.

 To register please click here.  Advance registration is necessary.

This program is supported, in part, by public funds from the New York City Department of Cultural Affairs, in partnership with the City Council.  Additional support is provided by The New York Landmarks Conservancy.