Everywhere you look and listen these days you can‘t help but be aware of the increasing focus on the issue of sustainability and energy conservation. Regardless of where one stands on the issue of climate change, sustainability, smart growth, renewable energy, etc., it is evident that as a nation, and indeed globally, we are seeing a momentum shift in the direction of escalating research, inquiry, development and broadened acknowledgement of the vast potential in "green" technologies. Of particular interest to us in the National Park Service (NPS) is how these emerging technologies potentially conflict with the goals of historic preservation, and specifically how projects associated with these technologies may impact historic properties, particularly National Historic Landmarks.
The National Historic Landmark (NHL) Program is administrated by the NPS, with responsibility for monitoring the condition and status of NHLs subsequent to their designation by the Secretary of the Interior. As part of the monitoring process, the NPS is responsible for reporting to the Secretary and the public any known or potentially detrimental threats to the integrity of our country‘s NHLs. (Integrity is defined as the ability of an historic property to convey its historical significance, associations and attributes).
In addition to monitoring NHLs to identify known or anticipated damage or threats to integrity, NPS provides assistance to NHL owners and stewards regarding appropriate, consistent preservation principles and practices. This guidance is provided in large part through The Secretary of the Interior's Standards for the Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring, and Reconstructing Historic Buildings. (There are also Standards and Guidelines available for Treatment of Cultural Landscapes). The Standards are responsible, common sense principles presented in non-technical language. They were developed to help protect our nation's irreplaceable cultural resources by promoting consistent preservation practices. There are Standards and accompanying Guidelines for four distinct, but interrelated, approaches to the treatment of historic properties--preservation, rehabilitation, restoration, and reconstruction.
Of the four treatments, rehabilitation is the most commonly used. It is defined as: the act or process of making possible a new or compatible use for a property through repair, alterations, and additions while preserving those portions or features that convey its historical, cultural, or architectural values. This treatment assumes that at least some repair or alteration of the historic building or landscape is required in order to provide for an efficient contemporary use.
Currently the Secretary of the Interior's Standards and Guidelines as written do provide information regarding the retrofitting of historic properties to increase energy efficiency. Although this type of work (such as installation of insulation or structural or mechanical retrofitting) is often an important aspect of rehabilitation projects, it is usually not part of the overall process of preserving character-defining features; rather, such work is reviewed and assessed for its potential negative impact on the property's historic character (defined as the sum of all visual aspects, features, materials, finishes and spaces associated with a historic property, i.e. the original configuration together with losses and later changes. These qualities are often referred to as character-defining.) For this reason, particular care must be taken not to obscure, radically change, damage, or destroy character-defining features in the process of rehabilitation work related to energy efficiency.
Although the NPS has been at the forefront of historic building weatherization guidance since the 1970s (i.e., publication of Preservation Briefs on "Conserving Energy in Historic Buildings," 1978--currently undergoing revision; "The Repair of Historic Wooden Windows," 1981; and "The Repair and Thermal Upgrading of Historic Steel Windows," 1984) the Standards were developed before the advent of the current "green building" movement and the rapidly evolving technology and materials now emerging.
In the 30+ years since the Standards were developed, the guidance on energy efficiency and renewable energy initiatives has not been updated to reflect the rapidly changing technologies in this field (http://www.nps.gov/history/hps/tps/briefs/presbhom.htm).
There are now many energy conservation initiatives and larger-scaled green projects currently available that are not discussed in the Standards. Such potential projects may include installation of wind turbines or spires, green roofs, solar/photovoltaic systems, geothermal and hydroelectric energy, and bioretention measures such as rain gardens and bioswales. If you, as an owner or steward of a NHL, contemplate a project to conserve energy and reduces costs, or educate others as to such benefits, what should you consider? As stated previously, the utmost concern is that the historic character and integrity of the NHL is not compromised by any action taken. Regardless of the size or scale of the project, the core concern remains—green projects must not introduce an intrusion or alteration to such an extent that the property loses its ability to convey its historic significance, or to adversely affect the qualities and characteristics that caused it to be originally designated.
It is critical that in the early stages of project research and planning you take a proactive stance and notify your NHL and State Historic Preservation Office contacts and other partners in the preservation community. It is more than likely that your local community will require review and approval through a planning commission or architectural review board. If the project will be funded by a Federal agency or a Federal permit, licensing or approval is needed, the responsible Federal agency is required to initiate Section 106 review, as specified in the National Historic Preservation Act of 1966. Section 106 requires agencies to consider the effects of their actions on historic properties—in this case, NHLs. Under Section 110(f) of this law, if the agency determines the project will adversely affect the NHL, every effort must be pursued to minimize potential harm to the NHL. (For more information on Sec-tions 106 and 110 and NHLs, see: National Historic Landmarks Program web site, "Federal Involvement with National Historic Landmarks").
You may have come across the statement "the greenest building is the one already built" or "existing buildings possess substantial investments of embodied energy"—meaning historic buildings should be considered a renewable resource, inherently sustainable. As owners and stewards of NHLs, you are contributing to the broad integration of historic preservation and sustainability. If you decide to move forward with a green project, we cannot stress enough the value of proper communication and partnership connections. The potential for open discussion and innovative ideas regarding green building techniques is limitless. The Standards, although neither technical nor prescriptive, provide essential guidance that is designed to accommodate a fair degree of flexibility. Green initiatives that acknowledge the philosophy provided by the Standards will benefit from open and constructive dialogue, a cooperative approach, incorporation of creative design solutions, and a judicious balance between retention of character-defining features and subtle integration of new green technology. The accepted definition of sustainability, "development that meets the needs of the present without compromising the ability of future generations to meet their own needs," embraces the mutually beneficial path of green initiatives and historic preservation. Following this approach and mind-set, the NHL program will give thorough consideration to the ideas you present.
Renewable Energy Projects, National Historic Landmarks, and The Secretary of the Interior's Standards and Guidelines
Additional Information and Relevant Case StudiesSecretary of the Interior’s Standards for Historic Properties with Guidelines for the Treatment of Cultural Landscapes
NPS: Weatherizing and Improving the Energy Efficiency of Historic Buildings (http://www.nps.gov/history/hps/tps/weather/index.html)
Advisory Council on Historic Preservation: Task Force on Sustainability and Historic Preservation Overview
National Trust for Historic Preservation: Sustainability and Historic Preservation (http://www.preservationnation.org/issues/sustainability/)
U.S. Green Building Council and LEED (Leadership in Energy and Environmental Design) (http://www.usgbc.org/)
Sustainable Sites Initiative
Whole Building Design Guide: Sustainable Historic Preservation (http://www.wbdg.org/resources/sustainable_hp.php)
American Society of Landscape Architects: Sustainable Landscapes (http://www.asla.org/sustainablelandscapes/)
Consult individual State Historic Preservation Offices (SHPO) websites for additional information on green technology and historic preservation.
Originally published in "Exceptional Places" Vol. 5, 2010, a newsletter of the Division of Cultural Resources, Midwest Region. Written by Geoffrey Burt.
Last updated: June 26, 2018