Resilience is in the Details of Historic Buildings
Event: Repairs and Replacements of Historic Buildings
Location: Center for Architecture, 02.16.10
Speakers: William Neeley, Jr. — Assistant Director, New York City Landmarks Preservation Commission; Monty Mitchell, AIA — Co-chair, AIANY Building Codes Committee (respondent); Walter Sedovic, FAIA — Principal, Walter Sedovic Architects (respondent)
Organizers: AIANY Building Codes Committee; AIANY Historic Buildings Committee
As much as anyone might want to demystify the workings of the Landmarks Preservation Commission (LPC), the approval process will never be a cut-and-dried matter. However, LCP Assistant Director William Neeley’s presentation clarified the criteria for designating landmarks and determining whether changes to landmarked structures should go forward. He also allowed that these procedures inevitably strive to balance priorities frequently in tension: integrity of original materials, aesthetics, context, and sustainability. What makes a building or district worthy of landmark status involves both its fabric and its visual effect, Neeley said; changes that some observers would consider inauthentic on close inspection may be essentially invisible when the materials are installed on a high floor. The interplay among the competing values, all occurring while building technologies evolve, ensures that the debates surrounding preservation and restoration remain irresolvable.
Neeley’s talk and the ensuing panel discussion focused on the process of working on landmarked sites, not the sociology and rationales of preservationism. He examined case studies such as the restored steel casement windows in the midtown Rockefeller Apartments, the downtown Potter Building’s wooden window sashes (with double glazing replacing inoperable single panes, plus a paint analysis resulting in recovery of the original rust hue), and the replacement of badly spalled terra cotta cornices in Jackson Heights with fiberglass-reinforced plastic. The last case falls into the complex policy area involving substitute materials; Neeley outlined the LPC’s requirements that deteriorated features be replaced by new units that match the original color, texture, size, and (where applicable) decorative details, preferably above eye level, producing a cumulative effect that doesn’t diminish a building’s integrity.
The respondents seconded Neeley’s emphasis on judgment calls. “The Buildings Department does not make clear distinctions between repair and replacement,” observed Monty Mitchell, AIA, co-chair of the AIANY Building Codes committee. The thresholds of what replacements are essential and what operations require a permit are sometimes resolved more ad hoc than through wholly predictable precedents. Safety-assessment requirements under Local Law 11 raise problems in buildings with distinctive features that predate current codes, Mitchell noted; the risk of fire spreading horizontally through combustible cornice materials shared by a row of old-law tenements is a common problem. Another variable in landmarked districts is that alterations must comply with the New York State energy code if at least 50% of a building system is replaced; building-wide window replacements reach this percentage, and an exemption affecting historic buildings is about to be removed by City Council (though how the Buildings Department will interpret this change, Mitchell said, isn’t yet clear).
Walter Sedovic, FAIA, of Walter Sedovic Architects, describing himself as a LEED early adopter and an advocate of “sustainable preservation,” raised the point that buildings erected before 1929 can perform as well as those of the contemporary green-building era in energy conservation. The problem buildings, he finds, are those of the 1930-2000 period. Authenticity and environmental performance, Sedovic argued, are often compatible values; the origins of many sustainability criteria are in features of traditional buildings, such as high thermal mass. “The issue here,” he said, “is how much Disneyfication are we willing to accept under the guise of the application of codes before our Modernist landmarks are eroded? Before the time that we actually figure out what it is that we’ve lost?”
The gauntlet that Sedovic laid down involved both appearance and performance. “We’ve been fooled in the past, and not in the recent past: in the distant past,” he cautioned, by materials manufacturers’ claims about durability that haven’t panned out. Pressed-iron galvanized roofing shingles, epoxies, and silicones have all come and gone as “savior” materials, he recalled, and “vinyl is final” has become a punchline (“If vinyl were final, why did Sherwin-Williams introduce vinyl siding paint?”). Any material, including today’s fiberglass components, deteriorates without maintenance.
Instead of endlessly experimenting, Sedovic recommended, architects and owners should apply the best available technical knowledge about materials and assess long-term benefits, not just initial costs. Particularly as “shovel-ready” stimulus money flows toward retrofits and repairs, he advised architects to pursue an agenda that best serves the built environment in the long term. “Throwing money out for a bunch of quick jobs to do something that has no lasting value is not stimulus,” he said. “With the inherent benefits of our historic buildings, our voice needs to become more collective and louder… What LEED is all about is relearning the things that we knew two generations and more ago.”
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