The 85-year-old National Academy of Sciences building in Washington, D.C., is being renovated from a private enclave for scientists into a more welcoming public space for lectures and other events, while incorporating daylighting and other features.
Many historic preservationists believe that the U.S. Green Building Council’s LEED rating system must be changed to better reflect the ecological, economic, and cultural value of preserving older buildings. Although LEED version 3 (also called LEED 2009), which came out earlier this year, does give more weight to retaining existing buildings than previous iterations, some believe USGBC should go even further. At the same time, there is talk about whether another venerated guideline—the Secretary of the Interior’s Standards for the Treatment of Historic Properties—also should be revised to reflect growing concerns about sustainability.
Last November, an informal group of about 30 preservationists, architects, environmentalists, and green-building professionals met at the historic Rockefeller estate at Pocantico Hills, N.Y., to talk about the nexus between green building and preservation. What emerged was the Pocantico Proclamation on Sustainability and Preservation, which outlines several preservation-based principles intended to form the basis for ongoing discussions about revising LEED and the Secretary of the Interior’s standards.
“At Pocantico, we discussed preservation policy in the 21st century, and, to a person, we agreed it was important for us in the preservation community to re-evaluate the tools we use and the policies we have to make sure they are meeting today’s needs,” says Emily Wadhams, vice president for public policy for the National Trust for Historic Preservation. “We want to get the value of heritage and the lessons learned from older buildings into common parlance.”
Setting the Standards
Although the Pocantico Proclamation still is being finalized, in a speech at last fall’s Greenbuild, National Trust president Richard Moe outlined six basic principles that should underpin sustainable preservation activities: 1) promote a culture of reuse; 2) reinvest at a community scale; 3) value the lessons of heritage buildings and communities; 4) make use of the economic advantages of reuse, reinvestment, and retrofits; 5) re-imagine historic preservation policies and practices as they relate to sustainability; and 6) take immediate and decisive action, especially with regard to such matters as updating LEED and promoting ongoing research into life-cycle analysis of building materials and embodied energy.
When it comes to re-imagining policies, there have been nascent discussions among some preservationists about whether the Secretary of the Interior’s standards should be revised to reflect sustainability. In March, for example, attendees at a conference about sustainability and preservation held at Goucher College in Baltimore repeatedly questioned whether the standards, which first were promulgated in the late 1970s, still are adequate to meet today’s sustainability goals. The standards, which include guidelines for preservation, rehabilitation, restoration, and reconstruction projects, were designed to be nontechnical and nonprescriptive, meaning they don’t outline particular solutions about which aspects of historic buildings should be saved or what materials should be used. Rather, the standards are meant to provide “philosophical consistency” to preservation projects while allowing some flexibility in how they are applied.
The National Trust believes the standards are adequate as written. “We don’t think the standards need to change,” Wadhams says. “We believe they are broad enough, but we should talk about how they address energy efficiency and sustainability. Older buildings are already a step ahead of the game in that they tend to be built with durable, long-lasting materials, retain significant embodied energy, and may take advantage of passive ventilation through operable windows. But we also think they can be made more energy-efficient, or they could reduce water usage, or they could have green roofs. We need to consider how to incorporate green practices without destroying the historic integrity of a building or the character of a neighborhood. There needs to be a balance.”
The visitor center for the Lincoln Cottage complex is housed in this 1905 Beaux-Arts building, which was restored using sustainable materials and earned a LEED Gold rating from USGBC. The project includes recycled-content materials, low-flow water fixtures, and vegetated bioswales.
Audrey Tepper, a senior historical architect with the technical preservation services branch of the National Park Service, concurs that the standards can work with sustainable preservation projects. “The standards encourage retention and repair rather than replacement, and that action alone is green,” she says. “We can work the standards around LEED and other rating systems.”
Others believe the preservation guidelines need to be overhauled. One interesting idea discussed at the Pocantico summit was to develop a rating system for preservation projects that more closely resembles the LEED system—such as “preservation silver,” “preservation gold,” and “preservation platinum.” For instance, an iconic building like George Washington’s Mount Vernon estate in Virginia might be labeled “preservation platinum.” In that case, it would not be acceptable to remove or damage its historic fabric just to make the building more sustainable. But a differently ranked historic building might have more allowances for green upgrades. It is likely that this idea will be brought up again and more completely fleshed out during future discussions among advocates of sustainable preservation.
“We have this stone tablet mentality in the preservation world, that Moses handed us the Interior Standards—and that’s not just a flaw, it’s an absurdity,” says Carl Elefante, a sustainable preservation expert and a principal at Washington, D.C.–based Quinn Evans | Architects. “The most important thing is for preservationists to understand the process of the green-building community. USGBC has adopted continuous improvement as part of its mission; it’s the notion of a cyclical process to adapt to new conditions and information.”
The S.T. Dana Building at the University of Michigan was renovated and restored, adding 35,000 square feet (3,252 m2)
to the 100-year-old building and incorporated daylighting, natural ventilation, recycled-content materials, composting toilets, and a radiant-cooling ceiling panel system.
Challenges and Opportunities
While preservationists debate the future of the Secretary of the Interior’s standards, they also are continuing to work with USGBC to revise LEED. They applaud LEED version 3 for promoting the retention of existing building stock. Released in April, the new system assigns different weights to various credits based on life-cycle assessment criteria. The rating system also encourages construction or renovations within a dense community, as opposed to greenfield construction, and offers an alternative compliance path that will promote the reuse of existing buildings based on the expected life cycle and durability of building materials.
The National Trust and its partners now are working with USGBC to further refine LEED to incorporate cultural, social, and preservation metrics, which may delve into less quantifiable aspects of buildings such as social sustainability, health and comfort, and social capital. Another Pocantico-like summit—with even more participants—now is being planned to coincide with the National Preservation Conference in Nashville, Tenn., in October.
There is much to discuss. Another major challenge facing preservationists is how to deal with the ever growing stock of modern-era buildings that will be considered historic as they age. Unlike old Victorian houses or other traditional buildings, modern buildings often rely on outdated mechanical systems or have inoperable windows. Preservationists will have to make difficult decisions about what counts as historic fabric and what can be removed or altered to make a modern building that has been deemed historic more energy efficient.
Finally, Elefante and others would like the growing sustainable preservation movement to think more often in terms of the avoided impacts of saving existing buildings—that is, instead of just determining the embodied energy of a structure, one might calculate the environmental, social, and economic impacts of new construction that would result from demolishing and replacing the existing building.
“It’s important for us to figure out how to be stewards to these cities we’ve inherited,” Elefante says. “The preservation community has to be as dynamic as the green-building world is today and recognize that improvement can happen.”
Kim A. O’Connell writes about architecture and sustainability from Arlington, Va.