Differentiated and Compatible Design

The Secretary’s Standards Revisited

Curiously, historic preservation has once again become a hot topic as architects, preservationists, public officials and citizen activists debate the criteria used to evaluate proposed additions to historic structures or infill buildings in historic districts. This comes in response to growing public opposition to recent decisions by some preservation authorities to approve starkly contrasting Modernist additions to historic buildings or dissonant new structures in traditional settings.
The debate has been particularly lively in New York City and Charleston, SC, where preservation commissions have approved a series of contrasting Modernist structures in historic settings. However, it has also aroused students, faculty and alumni at the University of Virginia, where the debate has spilled onto the pages of the student newspaper and the internet. In the historic center of Rome, Richard Meier’s Ara Pacis Museum stirred such intense opposition that upon being elected, the new mayor of Rome called for a referendum to decide whether to remove the new building!
If the purpose of historic preservation is to safeguard historic buildings and neighborhoods, how does one justify such recent interventions as Norman Foster’s glass tower on top of the landmark Hearst Building or Renzo Piano’s additions to the Morgan Library, to take but a couple of New York City examples? Weren’t the preservation laws passed decades ago precisely to prevent these kinds of intrusions on historic fabric? The debate has arisen now because we are seeing the logical consequences of policies developed decades ago when the architectural culture was quite different. Those policies now must be reconsidered in light of a changed landscape.
The key document of the post-war historic preservation movement in the United States is without question The Secretary of the Interior’s Standards for Rehabilitation. Drafted in 1977 by W. Brown Morton III, Gary Hume, Kay Weeks and Charles Fisher of the National Park Service (NPS), the standards defined criteria for determining the eligibility and compliance of preservation projects under the Tax Reform Act of 1976. In addition to the matching grants given annually by the NPS to the states in support of their local preservation programs, the act established federal tax incentives for the rehabilitation of properties in private ownership listed on the National Register of Historic Places. The NPS published the standards to formalize the review of projects applying for both of these programs. (They have been revised several times, most recently in 1995.)
These federal programs gave an essential boost to the vigorous “back to the city” movement that has renovated many of America’s historic centers from the late 1970s to the present. According to the NPS, by 2005 over $36 billion had been invested in over 33,000 projects nationwide. Historian and preservationist Calder Loth has pointed out that the rehabilitation tax credit program is “the only successful urban renewal program because it is the only one that has actually renewed urban areas.” While not in fact subject to them in many cases, local preservation officials have tended to use The Secretary of the Interior’s Standards for Rehabilitation to guide their own programs, lending the document a far broader authority than originally intended. Indeed, the standards have become the de facto national policy governing preservation activity in the United States.
The preservation philosophy enshrined in the standards was informed by the 1964 Venice Charter, the foundation of post-war preservation theory and practice, promulgated worldwide to this day by UNESCO. The charter declared that additions to historic monuments “must be distinct from the architectural composition and must bear a contemporary stamp,” revealing a prejudice in favor of Modernist design in historic settings. The standards, in their original version, were more moderate, having been designed to encourage rehabilitation rather than strict restoration and avoiding any direct reference to style. To their credit, the NPS provisions sought to strike a balance between doing justice to the historical and artistic significance of a site and promoting its continuance in beneficial economic use, which was after all, the main intent of the Tax Reform Act. This balance has, for various reasons, become noticeably weaker in recent years and a growing number in the preservation community believe a clarifying further revision of the standards is needed.
Setting Benchmarks
For the most part, the standards are unexceptionable, setting benchmarks for the appropriateness of rehabilitation work, emphasizing repair and renovation rather than restoration or reconstruction. They call for retaining and preserving the historic character of a site, “recognized as a physical record of its time, place, and use.” The standards recognize that “properties change over time; those changes that have acquired historic significance in their own right shall be retained and preserved.” Finally, the standards endorse the concept of reversibility, so that contemporary additions or alterations might be removed in the future without permanent damage to the historic fabric.
Other provisions have proved more problematic, such as the following passage in Standard Three: “changes that create a false sense of historical development, such as adding conjectural features or architectural elements from other buildings, shall not be undertaken” (emphasis added). There is a complex philosophical subtext underlying that italicized phrase, but the main intent of the provision was to prevent kitsch – including uninformed “traditional” design intended to make the building “look more historic than it actually was,” in the words of Standards author W. Brown Morton III. In the 1970s this was perceived as a real problem because the knowing application of traditional architecture was a rarity at the time.
Standard Three also banned the practice, common in the pre-war decades, of cobbling together buildings or entire districts by relocating elements or structures from other sites. Such practices as the creation of “period rooms” or “outdoor historical parks” raised the specter of fakery and potentially supported a market in architectural salvage that encouraged demolition or relocation of old buildings. But the reconstructions of medieval Spanish chapels and courtyards at The Cloisters (part of the Metropolitan Museum of Art in New York) or the remarkable Melrose plantation in Natchitoches Parish, LA, (with its congeries of wings and pavilions taken from houses about to be demolished nearby) are now considered historic partly because of their ingenious integration of salvaged pieces from elsewhere.
While the advisability of prohibiting such practices is at least arguable, Standard Three was also widely interpreted to preclude the addition of new features, no matter how informed or scholarly, in the same style as the landmark building or the later completion of an unfinished building according to its original design. This standard, for example, was the basis for the NPS denial of tax credits to the completion of the south wing at the Palladio Award-winning Kennedy-Warren Apartments in Washington, DC, featured in the July 2006 issue of Period Homes magazine.
The application was denied because the completion of the missing wing some 70 years after the original construction changed how the public would perceive the building “as it has come down to us in history,” according to the official of the NPS responsible for administering the program at the time. This is quite a stretch from the original intent of Standard Three.
Standard Nine has proved the most troubling due to its ambiguity: “The new work shall be differentiated from the old and shall be compatible with the massing, size, scale, and architectural features to protect the historic integrity of the property and its environment.”
While the standards do not call for new additions to be contrasting in character or require them to be in a Modernist style (as implied by the Venice Charter’s “contemporary stamp”), they do require new construction to be “differentiated” without defining how, by whom, or to what degree, and to be “compatible” without offering criteria for achieving a harmonious relationship. The standards do not suggest where the balance between “differentiation” and “compatibility” should be placed, leaving broad latitude for interpretation. In a less fragmented architectural culture this latitude would be welcome, but under current conditions – in particular, the aggressive stance of the contemporary avant-garde – it has led to confusion that threatens the fundamental mission of the preservation movement.
Differentiation vs. Compatibility
In practice, interpretation of Standard Nine has tended to prioritize differentiation over compatibility. For NPS reviews of projects during the last decade or so, the compatibility requirement was typically met by consistency of abstract relationships like size, massing and horizontal façade alignments to tie new and old together. Differentiation was usually achieved by using a readily distinguishable Modernist style, albeit “toned down” so as to qualify as “compatible.” An addition to a traditional building in the same style as the original would be disqualified under this reading of the standards because it would be seen as insufficiently differentiated. (This interpretation was personally explained to me by the same NPS official at a National Trust conference, in October, 2006. Current NPS practices may have changed under new leadership.)
This interpretation is also reflected in NPS literature. For example, the guidelines published by the NPS (and accessible on the NPS website) highlight preservation treatments which are described as either “recommended” or “not recommended.” In these examples a clear preference for Modernist additions has long been apparent; indeed, no traditional additions are illustrated. The large 1981 addition to the Newberry Library in Chicago by Harry Weese is offered as an example of “recommended” practice, despite its incongruous character – a scaleless, opaque-brick box added to the back of a robust and handsomely arcaded Romanesque Revival stone building that was left incomplete upon its construction. Here differentiation has altogether eclipsed compatibility, which is apparently satisfied by nothing more than maintaining the same building height and inscribing a shallow pattern of arch-like shapes in the otherwise unrelieved brick walls of the addition. (See the NPS website. )
The ambiguous language of the standards and the examples illustrated in the guidelines have persuaded numerous officials around the country to err on the side of differentiation, and in some places preservation commissions and officials have interpreted the standards as mandating Modernist design for new construction in historic settings, however discordant such interventions may be.
The city of Charleston recently considered rewriting its pioneering 1931 Zoning Ordinance, removing the existing requirements for conformance of new construction with the historical character of the district and instead simply referencing the standards. Critics of the old ordinance said that insisting on maintaining historical character in new buildings was creating a “simulated architectural environment” or “museum” city. Given their recent approvals of a number of high-profile projects proposing Modernist structures in the district, the proposal may be seen as an attempt by the local Board of Architectural Review to operate under what they saw as the more accommodating language of the standards. Ultimately, the city adopted a customized version of the standards that specifically avoids an implication that additions must be in a contrasting Modernist style or that new work in a historical style is insufficiently differentiated.
Numerous examples (including those pictured here) could be cited of local officials approving or demanding unsympathetic additions to landmark buildings and districts – decisions routinely justified by pointing to the standards. Growing opposition to such imposition of non-conforming interventions in historic districts has led to calls for further revisions to the standards to clarify the criteria for differentiation and compatibility in a way that is biased neither in favor of Modernist interventions nor against new traditional design, but simply sustains the character-defining elements of the place. Despite this emerging debate, a recent internal review by the NPS determined that there was no need for revising the standards at this time.
Overcoming Contradictions
The apparent contradictions of Standard Nine can be overcome, in my view, only by recognizing that the fundamental interests of preservation require that compatibility be prioritized over differentiation. This is necessary because the inherently oppositional attitude of Modernist architecture toward traditional buildings and settings must be counterbalanced by a sufficiently robust defense of historic character. To insist on differentiation by means of a contrasting Modernist style for new construction condemns historic (non-Modernist) buildings and districts to growth and change that is alien to their historic patterns and typologies. The gradual erosion of their historic character is then the inevitable consequence of the preservation effort itself – an unacceptable contradiction at the heart of contemporary preservation policy.
An altogether different attitude has been taken when making additions to Modernist landmarks, which typically are treated with far greater sympathy than those in traditional styles. Consider, for example, the controversy over the several failed proposals to make additions to Marcel Breuer’s New Brutalist Whitney Museum in New York – schemes proposed successively by Michael Graves and Renzo Piano – all rejected by the city’s Landmarks Preservation Commission as inappropriate. The same commission approved much more starkly contrasting additions to classical buildings, like McKim, Mead and White’s Harvard Club, Brooklyn Museum and Morgan Library, not to mention the Hearst Tower. (While these decisions were not governed by the standards, they reflected the preservation philosophy that mainstream policy-makers nationwide have adopted based on their interpretation of them.)
Conversely, federal preservation officials approved a seamlessly “replicative” extension to Eero Saarinen’s terminal building at Dulles Airport, which added additional bays identical to those of the original design. On the other hand, Kevin Roche’s extension of the Jewish Museum in New York was criticized precisely because its “seamless addition” was not sufficiently differentiated from the original traditional building. Clearly a double standard has been used to evaluate proposed additions: “differentiation” for traditional landmarks and “compatibility” for Modernist ones. Would it not be more reasonable to define one set of criteria for all projects, regardless of style, favoring compatibility over contrast?
Prior to the Second World War, additions to monuments in the same style were common practice – for example, in the gradual expansion of the Louvre in Paris or the United States Capitol in Washington, DC. We do not object to Thomas U. Walter’s cast-iron dome or House and Senate wings on our most important national monument because they were designed to conform to the style of Thornton, Bulfinch, and Latrobe’s work decades before. Indeed, this very large building has grown tremendously over the course of two centuries while retaining a remarkable stylistic unity. And yet, Walter’s work would likely not be approved under current interpretations of the standards, and recognizing this should prompt us to question the underlying philosophy behind present policies. It makes little sense to prohibit the very processes that brought our most treasured landmarks into being in the first place.
Stylistic Bias
The truth of the matter is that the doctrine of differentiation has been routinely used as a mask for stylistic bias. The standards and the Venice Charter on which they were based assumed that the Modernist aesthetic would be normative for contemporary building culture forever and sought to discourage any suggestion that preservation was an anti-Modernist enterprise. But preservation regulations, including the standards, should not be construed to require the acceptance or rejection of any proposed addition solely on the basis of style.
Additions may be in the same style as the historic buildings, provided that the new construction is consistent with the typologies, composition, scale, proportion, ornament, materials, and craftsmanship that define the historic character of the setting. Violation of these same attributes for the sake of a questionable theoretical principle simply leads to the loss of historic character and betrays the fundamental purpose of preservation. The key concepts should be respect for the historic resource and the cultivation of the appropriate – meaning the fitting and exemplary – not simply projecting the date of construction of each part of the building.
The only legitimate reason for differentiation – to avoid deception about what is actually deemed historic – can be addressed by requiring that new interventions in historic settings are distinguishable from the historic fabric by informed observers or trained professionals. No differentiation should be made that would result in an incongruous or ugly contrast, just as no addition or alteration should obscure or conceal the historic structure it joins. Where the new construction would not be readily distinguishable by the public at large, interpretive materials should clarify the construction history of the site rather than expecting this information to be self-evident from architectural appearance alone. The “contemporary stamp” required by the Venice Charter might be nothing more than the date carved into the new stone or a mark on the new bricks identifying them as belonging to a later phase of construction.
Drafters of policy regulations on this issue face a problem in basic logic. Differentiation has the advantage of being easy to define – simply make something different. Compatibility is more difficult to grasp because it is not clear how to draw together into an ensemble old and new work, particularly if the new is in a conspicuously different style. We get an idea how a compatible relationship among buildings of different eras may be developed by studying historic urban ensembles like the great European squares – the Grand Place in Brussels being an outstanding example – or American places revealing similar continuity of character over time and irrespective of style. In these cases we see that compatibility does not mean uniformity and buildings can be quite varied in size and style without sacrificing a sense of ensemble.
The way to make buildings from different eras and styles compatible is for them to share the same generative principles, sustaining a decorous conversation about space, structure, elements, composition (including arrangement and scale), proportion, ornament and character. If these principles are shared by the buildings along a street or around a square, they will be compatible, regardless of style. If the principles of some of the buildings are antithetical, no alignment of building heights or adjustments of massing will be sufficient to maintain a relationship of civility between them.
The NPS would perform a great public service if it were to clarify the intent of Standards Three and Nine to prevent their use as justification to exclude new traditional design. The preservation community would only benefit from guidance more attuned to the new pluralism in contemporary architecture and more accepting of the broader range of choice that architects and preservationists have before them. Second, it would be a great help if the NPS were to create a new set of guidelines including many of the projects that have appeared over the years in the pages of this magazine or have received a Palladio Award for sensitive additions, such as the Carhart Mansion addition featured in the September 2006 issue of Period Homes. These would make better exemplars than the buildings currently illustrated by the NPS. There is no shortage of good examples of new buildings in historic settings that are both “differentiated” and “compatible,” but our preservation officials must be persuaded to place the best of these in the “recommended” category.

By Steven W. Semes