Forum Journal & Forum Focus

50 Years Reconsidered 

12-09-2015 17:35

Advocates, practitioners, and scholars concerned with the preservation of historic resources from the recent past have often debated the tenet that saving recent past resources may require changing the basic framework of professional preservation practice in the United States. One of the prime candidates singled out for change is the use of the so-called “50-year rule,” a criterion established for the National Register of Historic Places stating that “properties that have achieved significance within the past 50 years shall not be considered eligible for the National Register” unless the property is of “exceptional importance.”1

The use of the 50-year guideline is intended to provide “the time needed to develop historical perspective and to evaluate significance,” guard against “the listing of properties of passing contemporary interest,” and ensure that “the National Register is a list of truly historic places.”2 As a model for state and local preservation programs around the country, the National Register evaluative criteria, including the 50-year age restriction, repeat themselves in myriad forms in the more than 1,000 state and local preservation ordinances in the United States.

The 50-year “waiting period” for evaluation of historic resources and the exceptional importance criterion are of central concern because of the remarkable rate at which younger resources are being lost with little or no consideration of their significance. Densification of suburban and urban environments, real estate markets where land is worth more than existing buildings, and the continual cycle of rehabilitation for commercial and retail structures threaten scores of recent past buildings and landscapes. It is rare that a contemporary historian has the luxury of 50 years to evaluate the significance of a resource. Without access to the incentives and protections that come with eligibility for or listing in historic registers, as well as the public endorsement of significance that designation carries, advocates for recent past resources often cannot find preservation solutions for important sites before they are lost forever.

The 50-year age guideline also increasingly places a barrier between preservation professionals and the public as our field increasingly seeks to help people protect the places that matter to them, rather than those that matter to scholars and critics. From Phillips Oil “76” Ball Signs to mid-century elementary schools, traditional and nontraditional preservationists are working to save places that they identify with personally and generationally. It is a mathematical fact that most of these places will be less than 50 years old, and an almost equal certainty that they will not qualify as “exceptionally important.” With the 50-year time limit in place across much of the nation, preservationists have few options or tools at their disposal to protect those resources that fall through the 50-year crack.

As the field of preservation increasingly embraces the recent past and the 50-year restriction approaches its own 50th birthday, it seems a fitting and worthwhile time to reexamine the 50-year waiting period. Understanding where the guideline came from, how we use it, and its advantages and disadvantages can help in deciding whether it is a help or a hindrance in stewarding the significant built environment. Important questions include whether the 50-year restriction is as useful and valuable at the local level as at the state and national levels, and whether our current standards for evaluative scholarship are sufficient for making sound preservation decisions. An essential part of this examination calls for considering what the preservation world would look like without a time-centered guideline, and how preservation as a movement and profession may need to change if significance is not necessarily correlated to age.

As a starting point for the discussion, this article offers a brief look at the origins and function of the 50-year guideline, its practical and philosophical functions, and some preliminary observations about what the preservation landscape might look like without the 50-year criterion by means of a brief survey of communities with no age criteria for historic designation.


Many preservationists assume that the 50-year criterion was developed in conjunction with the National Register program after passage of the National Historic Preservation Act of 1966 (NHPA). National Park Service historian John Sprinkle’s comprehensive history of the 50-year time limit, however, shows that the restriction was developed as part of the Historic Sites Survey, a predecessor of the National Historic Landmarks program created by the Historic Sites Act of 1935. Overseen by the National Park Advisory Board,the Historic Sites Survey was charged with identifying nationally significant sites worthy of both preservation and potential inclusion as federally operated sites within the National Park System. Over the 30-year period between 1935 and 1966, the Historic Sites Survey and National Park Advisory Board developed most of the criteria for significance and integrity that were later adopted for the National Register of Historic Places.3

The Advisory Board and Historic Sites Survey instituted an initial time parameter for the review of historic sites in 1937, narrowing its focus to properties dating from, or associated with events from, before 1870. The Advisory Board’s rationale for this narrowing in scope was to avoid “controversy, or the perception of controversial issues” associated with properties “pertinent to current or near current history.”4 Much like the 50-year criterion today, the Advisory Board’s 1870 cut-off date drew criticism. The American Society of Architectural Historians argued before the Advisory Board that highly significant examples of then “modern” architecture were frequently destroyed with no recourse because of the 1870 guideline, and further pointed out that the chosen date in no way represented a terminus for architectural value.5

The Advisory Board revised the 1870 cut-off date in 1952 in the course of reassessing the Historic Sites Survey program review practices. A board committee report determined that “structures or sites of recent historical importance relating to events or persons within the last 50 years will not, as a rule, be eligible for consideration under the standards,” thereby initiating what we recognize today as the “moving window” of 50 years.6 There is no evidence in the record as to why 50 years was initially chosen as a waiting period; it appears the board decided upon this as an arbitrary period because, in its judgment, this was sufficient time for proper historical perspective and a subsidence of controversy. The Advisory Board included the Historic Sites Survey 50-year age guideline in the 1965 criteria for the successor National Historic Landmarks Program, adding an exception to the criterion for properties of “transcendent significance.”7 Less than five months after the passage of the NHPA, the NPS instituted criteria and guidelines for the new register program, including the 50-year time limit, based on those developed by the Advisory Board.8

50 Years in Action

In reflecting on the origins of the 50-year criterion, it is clear that an age-based criterion served distinct political and practical purposes for the Historic Sites Survey and National Register program, some of which remain relevant today, some of which do not. The criterion limited pressure to review or designate properties associated with contemporary values and living persons, and offered a pragmatic solution for how to prioritize and review a large backlog of potentially historic sites.9 It is also important to note that the focus of the Historic Sites Survey was in no small part to identify potential National Park units, a substantially higher standard than is typically employed in recognizing historic sites under most preservation programs.

As currently employed in the National Register program, the 50-year restriction upholds the concept that the passage of time enhances our ability to understand, contextualize, and responsibly evaluate the significance of a resource. The passage of time (at least in theory) helps prevent designation from catering to architectural nostalgia rather than architectural history and ensures preservation of well-documented, well-understood, and meaningful history rather than that which is merely interesting or noteworthy. The requirement for “exceptional importance” also serves a distinct purpose, holding “underage” resources to a higher standard to ensure that recognition afforded the resource will stand the test of time.

The 50-year guideline continues to serve as a practical and philosophical threshold for evaluating significance and as such exerts tremendous influence on the workings of American preservation practice. The criterion has evolved to guide a wide array of preservation activities, including determining the scope of historic resource surveys, the level of consideration afforded in environmental and design review processes, and whether properties are subject to demolition delay review. As a common baseline threshold for historic designation at the federal and local level, the 50-year guideline also has power to influence eligibility for programs such as historic building codes, historic rehabilitation tax credits, facade improvement and rehabilitation projects, and grant funding.

While the rationale for the 50-year time limit and exceptional importance criterion reads quite sensibly, recent-past preservationists can attest that these standards have perhaps unintended negative effects on how the preservation field views and values the recent past. As a time parameter, the 50-year cut-off stands as a philosophical boundary for preservation activities, indicating, however imperfectly, where we believe that the past typically “ends” and the present “begins.”10 Preservation is a movement rooted in time, and the reasons why society seeks to preserve past aspects of the built or designed environment stem from an underlying belief that what is old is valuable and meaningful to modern society.

Unfortunately, many preservationists see the 50-year cut-off not only as a necessary period of distance for reliable evaluation but also as a philosophical line separating quality from inferiority. The concept of “old” being valuable and meaningful can easily transform into a less-defendable value judgment that what is old is inherently better than what is new.

The “exceptional importance” criterion serves to further segregate the recent past by holding more-recent resources to a higher standard than their peers. In some modes of interpretation, the requirement is understood as meaning that only iconic, critically acclaimed, or nationally significant resources from the recent past are “good enough” for protection, while the vernacular fabric we so highly value in other historic contexts has less worth if it was developed during the last two generations.

While the National Register program clearly states that the 50-year criterion is not meant to exclude or prohibit resources from being considered for listing, in practice, the percentage of resources in the National Register with periods of significance ending in the previous 50 years is quite small. Since the mid 1970s recent past resources (those less than 50 years old at the time of their inclusion) have made up approximately 3 percent of National Register listings, with 40 percent of that number holding significance at the local level.11 The percentage of resources listed in the National Register built less than 50 years ago as of today (i.e., during or after the 1960s) is presumably even lower. There is no research available, or even easily compiled, on the number of designated properties less than 50 years old at the state or local levels, but it is likely that the percentage is similar to the National Register, with higher and lower percentages corresponding to differing patterns of historical development and concentrations of resources.

What If Dates Didn’t Matter?

While some preservationists welcome an end to the 50-year and exceptional importance concepts, others view their loss or liberalization with concern. Some preservationists foresee unending review, overwhelmed preservation commissions and staff, blown budgets, controversy sparked by groups vying for validation via the historic designation process, and public relations disasters as the broadened scope of potential significance collides with the public’s concept of what is, or should be, “historic.” All of these issues are important to address in any reconsideration of the 50-year criterion.

A number of communities in the United States, by chance or design, have already forded the 50-year gap, and manage preservation programs with relaxed or no age criteria for designation. These communities can offer an instructive look at how removing age from the significance equation affects program administration, preservation of recent past resources, and public perceptions. The group includes some of the country’s largest cities, such as San Francisco, Los Angeles, Chicago, and Raleigh, N.C., all of which have no age guidelines in their preservation ordinances. The list also includes places as diverse as Palm Springs, Calif.; Fairfax County, Va.; and the Colorado communities of Boulder and Aspen. Notable cities with age guidelines of less than 50 years include New York City and Seattle (30 years and 25 years, respectively).12

A brief survey of programs in communities with age standards differing from the National Register model revealed several threads for further inquiry. Most of the surveyed communities have designated properties from the recent past with significance at the local and national levels.The resources include nationally recognized and regionally important architecture, as well as sites associated with notable local or wide-reaching history. A fair number of the locally designated sites were also listed in the National Register, though many were not. For instance, Palm Springs maintains a number of locally designated modern-era sites, but counts no structures in the National Register.

The number of recent past properties designated locally, however, is not significantly greater than at the national level, remaining between 2 and 4 percent of total designations. In several communities, there were no resources at all less than 50 years old listed in the local register. These data can be viewed in several ways. On the one hand, it shows that removing an age criterion does not necessarily lead to a flood of nominations and listings, or listings of questionable quality. It demonstrates that solid scholarship and evaluation can reliably ensure that historic designations have lasting value. On the other hand, the relatively low number, and in some places the dearth of listings, may again testify to the undue influence of the 50-year criterion on the conceptual framework of preservation. Survey, scholarship, advocacy, regulatory review, and nominations for listings may be similarly low or absent.

The survey of communities with relaxed or no age criteria also showed that operating without an age guideline is not without its pitfalls. Staff in the local preservation program in Aspen, Colo., for example, have worked proactively for more than ten years to designate some of the city’s later 20th-century heritage, including examples of modern, rustic, and chalet-style homes. Their efforts have unfortunately stirred up public controversy over why the sites proposed for designation should be considered historically significant. In response, the Aspen municipal government has redeveloped and refined criteria for designation of recent past heritage a number of times, relying on detailed context studies, analytical scoring of integrity, tiered significance matrices, substantial incentives, and owner consent requirements for designations of some properties. A local task force has been convened to do more major revamping of Aspen’s designation criteria. Aspen’s experience underscores the fact that education, outreach, and solid scholarship—foundational elements for any preservation program—are even more critical when a local preservation program begins to expand beyond the boundaries of what the community traditionally (but perhaps inaccurately) considered “historic.”

More detailed study of communities without the 50-year age guideline would serve to inform development of preservation policy regarding resources from the recent past in a number of ways. Important questions to explore include what kinds of obstacles local historic preservation commissions and staff encounter from an administrative, historical, and public relations point of view when there is no recommended or mandatory waiting period for examination of a resource. It would also be worthwhile to investigate whether the relaxed age guidelines have been useful in saving or preserving recent past resources, and how designation of more-recent resources affected public perceptions of preservation. A compilation of best practices now being used by communities to review and evaluate, designate, and manage traditionally “underage” historic resources would help pave the way for other communities to consider similar relaxation or removal of age criteria from their historic preservation program.

The Next 50 Years

Questioning the validity of the 50-year criterion is a critical expansion in our conceptualization of significance and the cultural value of preservation, marking a desire to preserve a continuity of resources that link us to a time we no longer relate to.13 Reexamining an evaluation standard that is so philosophically and practically influential is challenging, and must include an understanding of the functional, conceptual, and historic context of the standard, as well as a weighing of the potential benefits and detriments of change. Yet there exists no better opportunity to undertake these efforts.

We must move forward, confident in the wisdom that we have much more to gain from employing a spirit of inclusiveness in preservation than we may lose in confronting controversy. Almost 50 years after the institution of the National Historic Preservation Act, preservation finds itself repeatedly grappling with overly restrictive regulations that effectively hinder historic preservation of significant American properties. It is our responsibility, as the stewards of historic resources, to re-assess the purpose of this restriction and discuss practical modifications that are needed to ensure higher efficacy and wiser implementation of preservation standards throughout the country.

Elaine Stiles is a program officer for the National Trust’s Western Office.


1 National Register of Historic Places, How to Apply the National Register Criteria for Evaluation; available from; accessed 4/2010.
2 Marcella Sherfy and W. Ray Luce, Guidelines for Evaluating and Nominating Properties that Have Achieved Significance Within the Past 50 Years; available from; accessed 4/2010.
3 John H. Sprinkle, Jr., ‘Of Exceptional Importance’: The Origins of the ‘Fifty-Year Rule’ in Historic Preservation,” The Public Historian 29, No. 2 (Spring 2007):82.
4 Ibid., 83-84.
5 Ibid., 87 and footnote 15.
6 Ibid., 84.
7 Ibid., 87.
8 Ibid., 99.
9 Ibid., 83.
10 Richard Longstreth, “When the Present Becomes the Past,” Past Meets Future: Saving America’s Historic Environments, Antoinette J. Lee, ed. (Washington, DC: The Preservation Press, 1992):249; and Richard Longstreth, “The Significance of the Recent Past,Cultural Resource Management, 16, No. 6 (1993):5.
11 Sprinkle, Of Exceptional Importance, 102; and  Carol D. Shull and Beth L. Savage, “From the Glass House to Stonewall: National Register Recognition of the Recent Past,” Preserving the Recent Past 2, Deborah Slaton and William G. Foulks, eds. (Washington, DC: Historic Preservation Education Foundation, National Park Service, Association for Preservation Technology International, 2000):1.
12 This is not a comprehensive or complete list of communities with relaxed or no age criteria for designation of historic properties. Undoubtedly more exist; this list was compiled based on easily available information in preservation-related publications, secondary source materials, program interactions, and announcements of landmark designations.
13 Longstreth, “Significance of the Recent Past,” 5.

Publication Date: Summer 2010

#Modernism #ForumJournal

Author(s):Elaine Stiles