“When we build of stone, let us think we build forever.” John Ruskin, 8 February 1819 – 20 January 1900
Sustainability: “meeting the needs of the present without compromising the ability of future generations to meet their own needs”
World Commission on Environment and Development (Brundtland Report), 1987
Reduce + Reuse = Preservation- a presentation concerning green preservation
The analysis of the green design and preservation equation begins with a philosophical discussion about the nature of these two design approaches.  This is not the first discussion on this topic. The theme of the 4th Annual US/ICOMOS symposium in Philadelphia in 2001 was entitled “Managing Change: Sustainable Approaches to the Conservation of the Built Environment.” The proceedings of that conference were published by the Getty Institute and several authors ventured into abstract underpinnings and planning issues. Since that time, the emergence of tools for measuring green design means that the discussion can also move into more detailed, technical areas, which moves the discussion from philosophy to many real and measurable attributes of buildings, both new and old.
The tools of green
One of the special challenges to this intersection has been an examination  of the tools that attempt to measure sustainable design. The exponential growth of the United States Green Building Council (USGBC) in the last five years stems from their LEED evaluation tools (Leadership in Energy and Environmental Design), which has become the default basis for evaluating green design in the United States. These tools do not currently give much value to building reuse. The underlying roots of this imbalance and potential methods of addressing this imbalance are part of several discussions. The concept of life cycle analysis, which is familiar to preservationists, is now becoming an integral tool of the eco-designer.
The lessons of history:
 Historic preservationists have a special insight into projections of the future because of our understanding of the past. The past teaches us that our ancestors built structures that used indigenous, renewable materials and produced buildings that responded to local climatic conditions. Historic buildings had many attributes that are now promoted as green design. Operable windows that allow fresh air and daylight, compact building form that is more efficient to build and heat, and cisterns that captured rain water were all common to late 19th century homes. These are now championed as “green.” Equally important are historic patterns of development. Homes in tight proximity to their neighbors meant that daily life was “pedestrian friendly.” Downtown buildings shoulder to shoulder were very energy efficient. Anyone looking for a planning model of a society that used a lot less fossil fuel per person could look at virtually any city that developed in the era before petroleum. In terms of density and land planning, the city of the 2060s may be more like the city of 1860 than it is the city of 1960. Preservationists and “smart growth” advocates are both aware of this common value, but it is not easily found with the “green” value systems. Few of our authors have ventured into this topic, which is highly relevant but is more common to urban planners than it is to building scientists. Historic preservationists know quite well how traditional urban neighborhoods function from cultural, social, and economic perspectives, and it is quite easy to add the ecological analysis to the discussion.
Energy
Virtually all models of sustainable design have at their core strong principles of energy conservation and efficiency. The “end of cheap oil” is a part of the near future, and the depletion of fossil fuels could be the single greatest challenge of the 21st century. Mankind’s two-hundred-year-long oil binge has brought with it incredible improvements in the world’s economy. The end of this gift from the long past is nearing and preparation for a future dominated by renewable energy sources dawns. Because of this, virtually all strategies of green design  have energy conservation and efficiency strategies as part of their core measurement. Several authors address this topic in the technical evaluation of building materials. The most important of these is the discussion on windows, which has been a flash point for preservation concerns for years. This topic is often one that appears to put preservationists at odds with green designers, which is why this is such a critical area for detailed technical and life cycle analysis. An article on the use of insulation within building cavities is sure to bring a new challenge to the building science of energy efficiency and building conservation. The long-term performance of building assemblies is the question, with a potential conflict between the common strategies for energy efficiency and the building science of durability.
Another area of needed discussion between preservationist and green designers is that of energy conservation codes. Historic buildings are currently exempt from energy conservation codes. This can give the appearance that historic property owners are unconcerned about energy conservation, which is not the case. This exemption should be a call to the historic preservation community to develop a special chapter for historic buildings within the energy conservation codes, just as these chapters exist in accessibility codes and life safety codes. Preservationists need to advance this discussion, and the APT sustainability committee represents a natural alliance of the professionals that can make this advancement. Energy conservation and efficiency can and should be a part of every historic building management and renovation project.
The subject of embodied energy is another method of integrating the ecological value of a historic building into the sustainability equation. If the ecological mantra is “reduce, reuse, recycle,” re-using historic buildings should be preferable to building new structures based upon the savings in embodied energy. This is a subject that received some attention 25 years ago but has not been advanced or integrated into green building strategies – to the detriment of both preservation and green design. I f is more than fair for preservationists to ask the question of whether or not a new building should be considered to be green if it replaces and existing historic building? The ecological equation of embodied energy and operational energy both have to be examined for an accurate green assessment to this question. Preservationists and green designers both need to be working on this math. The science of embodied energy calculations should become a part of the technical training of preservation professionals. Future Historic Structure Reports and Environmental Assessment Reports might include this as another base line value for the property being assessed.
Conclusion:
The art and science of sustainability is based upon the three E’s - environment, economy and equity. Advocates of sustainable design are using these principles to quantify ecologically beneficial building characteristics. The relative merits of wood versus concrete or the positive feeling and energy efficiency of natural daylight are just a few of the areas under discussion.  Unfortunately, in this effort to quantify how we build, the eco-equation doesn’t seem to be asking the question of why we build at all, or even much about where we build. For those of us who practice historic preservation, we have been challenging society to see the value of reusing historic buildings. This experience has taught us that buildings, no matter how well built, buildings will only be sustained if they are seen as having a positive cultural and economic value. We should now add to this list their ecological value. The historic preservation movement, as a profession and an approach to the treatment of the built environment, is doing something much more important than defining how to build. We are advocates for historic buildings, but we are also building a culture that sustains design. This may be our most important contribution to the science and art of sustainability.
Mike Jackson, FAIA
Illinois Historic Preservation Agency
Reduce + Reuse = Preservation - a presentation concerning green preservation |
