Forum Journal & Forum Focus

The Secretary’s Standards and LEED: Where they Work Together and Where they Diverge 

12-09-2015 17:35

"Cultural resource preservation is intrinsically a form of sustainable conservation. The built environment represents the embodied energy of past civilizations… historic preservation is conservation in every sense of the word.”1

Preserving a building is often called the ultimate recycling project, yet preservationists commonly fight the stigma that historic buildings are inefficient and require daunting corrective measures to retrofit with energy saving devices and systems. Green and sustainable design has become an increasingly popular issue in both the preservation and new construction industries. This article will identify the basic principles behind sound preservation practice and green design— when they work well together and when they do not. Preservation and “green” goals overlap, and reconciling their differences is possible, provided both sides strive to be as creative and flexible as possible.

Two different sets of guiding principles are the focus of this discussion: The Secretary of the Interior’s Standards for the Treatment of Historic Properties, and Leadership in Energy and Environmental Design, more familiarly known as LEED.

The Secretary’s Standards

The Secretary’s Standards lay the groundwork for sensitive preservation practice in the United States and were implemented to ensure that historic resources are protected. They are used by nearly everyone in the preservation field on local, state, and federal levels.

Two terms commonly used in the Standards— and in historic preservation in general—are important for this discussion: the “historic character” and the “integrity” of a property. “Historic character” is, in essence, the things that make a building special—its “visually distinctive materials, features and spaces,” for example, or the architectural styling of a structure or its unique methods of construction or craftsmanship. 2 Historic
character may include the features that distinguish one building from another—a dome, smokestack, steeple, grand staircase, stained-glass windows, or mosaic tile floor. The character of a historic building may also be defined by its simplicity, as in a more industrial or modern structure, where a stripped-down appearance is part of its inherent character. “Integrity” refers to whether or not a building retains these
important “character-defining” features and has not been inappropriately changed over time. These two concepts are central to the preservation of historic buildings. Therefore, modifications undertaken to make historic structures more sustainable must be sensitively done to retain the buildings’ character and integrity.

There are four standards for treatment:  Preservation, Rehabilitation, Restoration, and Reconstruction. The Rehabilitation Standards are the most flexible and the most commonly used. The Rehabilitation Standards take into account changes buildings encounter over time and provide the opportunity for reuse, provided character defining features are not destroyed.

When historic buildings are rehabilitated according to these standards, including any changes undertaken to make them more environmentally friendly, it is important to preserve historic materials. If original materials are intact—whether inside or outside the building—they should be retained and repaired whenever possible rather than replaced. This includes, but is not limited to, masonry, siding, roofing, porches, doors, windows, stairs, fireplaces, flooring, trim (and associated millwork) and wall finishes, as well as the historic layout of the building (floor plan, patterns of circulation). The requirement to retain or recycle materials also supports sustainability.

The historic character of a building should also be preserved, even if its use changes. If, in the attempt to make a property more energy efficient or sustainable, the integrity of a building (or its surroundings) is dramatically changed by removing or unsympathetically modifying character-defining features, the Secretary’s Standards are violated. The Standards are not prescriptive; treatments, in general, are not specifically allowed or disallowed. There are always ways to improve energy efficiency, but they must be undertaken with care to protect the integrity of the historic resource.

Leadership in Energy and Environmental Design

Established by the U.S. Green Building Council in 1998, Leadership in Energy and Environmental Design (LEED) is the “nationally accepted benchmark for the design, construction and operation of high performance green buildings.” 3 LEED rating systems promote the production of buildings that are sustainable and economically feasible and that will not harm the health of their occupants. The LEED rating system awards points when sustainable practices are incorporated into construction projects. The higher the point total, the higher the certification level achieved (Platinum, Gold, Silver, etc.). Similar rating systems exist, but LEED is the most widely known and the most popular nationally.

To be considered sustainable design, a project should try to meet the following six general principles. If flexibility is afforded and work is undertaken sensitively, the majority of these may successfully be included in preservation projects that also meet the Secretary’s Standards.

1. Site potential must be optimized.
2. Energy consumption must be minimized.
3. Water must be protected and preserved.
4. Environmentally preferable products should be used.
5. Indoor environmental qualities should be enhanced.
6. Operational and maintenance practices must be optimized. 4

Where the Secretary’s Standards and LEED Diverge and Where They Work Together

Few points are given by LEED for saving historic building materials. Although retaining cultural resources is the intent of some LEED credits, the current system does not take into account the full value of preserving our cultural heritage through saving historic buildings. LEED was initially conceived as a program to rate sustainable new construction. As a result, it grants few points for saving materials already in place. Far more points are available for the use of new materials. This makes little sense if you consider the energy it takes to produce new materials meant to replace architectural fabric that already exists. This discrepancy fails to meet the goals of either preservation or sustainability.

Credits are not given when historic buildings are inherently efficient. Because a building is “old” does not automatically mean it is inefficient. Yet LEED does not generally recognize this fact and requires changes that may irreparably damage a historic building’s character. Older buildings were commonly designed to take advantage of their sites and to maximize energy efficiency. Built before modern technology took hold, they were often sited to exploit solar gain so interiors could be illuminated and warmed. Operable windows, monitors (raised roof inserts with ventilation), and clerestories were incorporated not only to prevent moisture entrapment but also to cool structures in warm weather. Simple features were also added to shade interiors, such as overhangs, eaves, and cloth awnings. These add character to the exterior and make indoor spaces more habitable.

Durable building materials such as thick masonry have insulating properties as well, for which LEED offers no credits. Demolishing a historic interior to get the maximum amount of insulation in place may produce a more energy-efficient building, but will destroy a piece of history in the process. A historic building may certainly be upgraded with insulation, provided the insulation is placed in easily accessible locations that will not compromise the building’s architectural integrity. In fact, most air escapes vertically, so it should be a top priority to insulate attics, followed closely by basements and crawl spaces. Conveniently, these areas are generally secondary spaces where insulation can be installed with minimal impact.

Few points are given for the durability and long life cycle of traditional building materials. Traditional building materials, if properly maintained, may last for generations. LEED does not adequately recognize the long life spans of these materials, nor the fact that retaining them keeps debris out of landfills. Energy is also saved if it is not necessary to manufacture and transport new materials.

The success of today’s lumber industry depends on how quickly a tree can grow before it is harvested and milled for the construction market. The young timber used today is significantly less durable than its historic counterpart and deteriorates at a far more rapid rate. So even if “certified wood” (wood that is grown with environmental concerns in mind)5 is used to satisfy LEED credit requirements, the building is still receiving a product inferior to the old growth lumber that may already be in place. Moreover, historic wood will last longer if properly maintained. This is just one example of the numerous benefits of reusing what is already there and what was built to last.

New energy-efficient components may compromise a historic building’s integrity.  LEED encourages the use of features that conserve and capture energy passively.6 Examples of these include solar panels, photovoltaic cells, and roof gardens. Although there is much to gain through their installation, if they are too prominently placed on a historic building, if they require the removal of significant amounts of architectural fabric for their installation, or if they alter important spaces or the surrounding landscape, these treatments will fail to meet preservation goals. Care should be taken to locate equipment in the least physically and visually intrusive locations to diminish its presence.

As the research into and marketing of green building products increases, new, innovative materials are likely to become available. For example, roofing shingles that absorb and store solar energy might be appropriate in certain applications. Another alternative is placing a series of smaller solar panels hidden behind a parapet, as opposed to a single, large solar panel insensitively placed in the middle of a roof.

LEED points are granted for recycling demolished materials, as well as salvaging materials. The Secretary’s Standards discourage the demolition of historic materials, so removal of original fabric should be avoided. There are instances when removing incompatible, modern changes made to a historic building is merited, and when historic rehabs can benefit from the LEED points available for recycling a percentage of construction debris. LEED, however, gives more points for repurposing salvaged materials within a project than actually saving the materials in place, which is problematic. Recycling significant architectural fabric should never be undertaken merely to achieve a higher point rating. 7

LEED fails to acknowledge that historic windows are important features and that their energy efficiency can be upgraded. LEED encourages the use of highly energy efficient windows, which often requires the removal of historic windows that are potentially reusable. Moreover, original windows are character-defining features of historic buildings and their removal can significantly alter a structure’s integrity, thus conflicting with preservation goals and the Secretary’s Standards.

With proper maintenance, windows built from old-growth wood can function indefinitely and their performance can be substantially bolstered by using storm windows, caulk, and weather-stripping. Studies have shown that these simple improvements can result in efficiency similar to that of new insulated glass windows. Modern windows also have a relatively short lifespan and can be difficult, if not impossible, to repair. Once modern windows fail, there are few ways they can be recycled, and they will likely end up in landfills. This begins an environmentally insensitive cycle of removal and replacement.

Therefore, the most responsible approach is to retain historic windows that last and retrofit them for increased effectiveness rather than install new windows that, without exception, will fail and cannot be repaired. Regrettably, the replacement window industry is strong, and old windows are touted as poor performers, so the common practice of replacing windows is not likely to change much in the immediate future. To combat this, LEED should consider awarding points for the repair and continued use of old windows where significant improvements in energy efficiency are demonstrated, as well as where significant amounts of historic fabric are being retained and reused.

Restricting water usage can harm historic landscapes. “Cultural landscapes” 8 often play central roles in the overall makeup or character of historic properties. They also need water to survive. Therefore, like historic structures, they must be cared for and respected, even historic plantings that may not be native species.9 efficient irrigation systems may be used to save water, and recycled “grey” or rainwater may be captured for use in gardens and surrounding landscapes. But restricting water for irrigation to achieve the percentage savings required by LEED may irreparably change the important relationship between a building and its surrounding landscape. Unfortunately, there are no previsions within LEED for exempting cultural heritage areas from these calculations. 10

Few credits are given for reusing existing infrastructure in non-urban areas. Historic buildings seeking LEED certification located in urban settings may benefit from several “Urban Redevelopment” 11 credits, but  structures in more rural settings cannot. Rural locations may also have infrastructure in place such as roads, public transportation systems, and utilities. This infrastructure can easily be reused or updated, even if it is used less frequently and remotely sited. Existing features may require repair; however, reusing what is already in place will greatly reduce energy expenditures and save on the high costs of excavation, re-grading, producing and transporting new materials, and installation.

Some points are easily awarded by LEED without adversely affecting the integrity of a historic building. Purchasing green power from renewable energy technologies is one of the easiest points to obtain in the LEED rating system and one that will have no impact on the character of a historic building. 12 Other noninvasive ways to boost LEED points are to sensitively install energy efficient lighting, heating and cooling systems, and low-flow plumbing fixtures.

Carpeting and cabinetry made from recycled materials can be purchased from green building product suppliers. Counters and floors can be wiped down with environmentally friendly cleaning products. These changes tend to be reversible treatments, although care must always be taken to respect the historic nature of properties during their installation.

Revisions to LEED

Revisions to the current version of LEED are underway. The following changes should increase the number of historic preservation projects meeting the Secretary’s Standards and LEED:

1. Points will eventually be awarded according to “Life Cycle Analysis Indicators. 12 This will benefit historic buildings constructed with durable materials that do not require replacement.

2. The LEED rating system will increase from a total of 69 to 100 points.

3. Points relating to historic buildings may eventually be higher and allocated more efficiently.

4. To address many of the concerns raised in this article, the organizations administering LEED are working closely with and seeking comment from historic preservation advocates and the general public. 13

Conclusion

The Secretary’s Standards for Rehabilitation and LEED sometimes diverge in specific applications, but the objectives of the two entities are compatible.

Preservation keeps our nation’s history and culture alive and we learn much from the methods and practices of those who came before us. With our threatened environment, it is imperative that we make sustainable living a part of our lives. The public benefits of both preservation and sustainability are very clear and there is no reason why these goals cannot work together. Revising the current version of LEED to better account for the social values and environmental benefits of preserving historic structures is a good start. The discussion, however, must continue to engage the preservation, sustainability, and construction communities to assure the best possible outcome.


NOTES

1“Guiding Principles of Sustainable Design,” United States Department of the Interior, National Park Service, Denver Service Center, September 1993, p. 30.

2“Walk through Historic Buildings—What is Historic Character?,” United States Department of the Interior, National Park Service, www.nps.gov/history/hps/tps/walkthrough/start.htm.

3What is LEED?, www.usgbc.org/DisplayPage.aspx?CMSPageID=222.

4Referenced from the “Whole Building Design Guide (WBDG),” a comprehensive website for the construction industry with a strong emphasis on sustainability and green building practice, www.wbdg.org/design/sustainable.php.

5“Materials & Resources; Certified Wood,” LEED for New Construction & Major Renovations, p. 56, www.usgbc.org/ShowFile.aspx?DocumentID=1095.

6“Energy & Atmosphere; Renewable On-Site Energy;” LEED for New Construction & Major Renovations, p. 36.

7“Materials and Resources, Materials Reuse and Recycled Content,” LEED for New Construction & Major Renovations, pp. 49–52.

8“Guidelines for the Treatment of Cultural Landscapes— Defining Landscape Terminology,” United States Department of the Interior, National Park Service, www.nps.gov/history/hps/hli/landscapeguidelines/terminology.htm.

9“Sustainable Sites; Site Development: Protect or Restore Habitat,” LEED for New Construction & Major Renovations, p. 16.

10“Water Efficiency,” LEED for New Construction & Major Renovations, pp. 24–28.

11“Sustainable Sites,” LEED for New Construction & Major Renovations, pp. 8–22.

12“Energy & Atmosphere; Green Power;” LEED for New Construction & Major Renovations; p. 42; http://www.usgbc.org/ShowFile.aspx?DocumentID=1095

13Information from Barbara Campagna, AIA, LEED AP, National Trust for Historic Preservation. The version of LEED currently under review is LEED Version 3.0—2009. A more developed version will be LEED Version 3.0



Publication Date: Spring 2009

#ForumJournal
#LEED
#GreenGuidelines
#Sustainability

Author(s):Audrey T. Tepper
Volume:23
Issue:3