Written by Isabel Morris
We need quality buildings to safely house our schools, hospitals, offices, and our homes. We also live in a world with limited resources for constructing and operating new buildings, which means we need buildings that are sustainable and resilient in addition to being safe and functional.
Most cities facing this challenge are full of underutilized historic buildings and sites with cultural, social, economic, and technological value. These historic places are precisely the solution required in growing cities, and they have surprising economic and environmental benefits.
Since the 1987 Brundtland Commission’s Report, “Our Common Future,” sustainability has been defined as the ability to meet the world’s current needs without compromising our ability to meet them in the future. This sustainable development, in construction and civil engineering, manifests itself in the environments we build and inhabit: cities. Here, perhaps especially, it is important to balance a building’s quality of life improvements with its environmental and social consequences. From “mega tall” skyscrapers, to slums, to the infrastructure that connects them, cities can be catalysts for economic opportunity, industry, and innovative constructions. Historic buildings are a tangible recording of a city’s story and can teach us not only about our history and culture, but also about sustainability.
As catalyzing drivers of development, cities seem to be in direct opposition with historic structures. Cities need buildings that are safe, resilient, efficient, and accessible…but how? What happens to old buildings that stand in the way of new projects? How do we measure and balance the value of historic buildings with the value of progress and modern sustainable building practices? The momentum of development and emerging green technologies drive cities to build for the future. At first glance, run down historic buildings without some modern features (like adequate steel reinforcement or airtight window frames) seem to stand in the way of city and human development, where it is much easier to opt for cheaper, faster, and larger buildings than investing in an existing building.
Why consider historic structures? Historic buildings can be buildings of any style, construction method, period, or function; important historical sites in the US range from the sites of the 1969 Stonewall uprising to 12th century Acoma Pueblo. Most of the world’s historic buildings and sites are protected by legislation and active conservation organizations, which recognize the invaluable artistic, historical, social, and scientific importance of these places. In addition to these less tangible values, heritage structures have a proven record of longevity and resilience in the face of two millennia (or more) of natural and anthropogenic hazards. Historic buildings are fascinating because they function as both sociocultural bulwarks and priceless repositories of technological advancements. Many of the world’s historic sites are “good” buildings that can teach us important lessons about sustainability and building construction.
By “good” buildings, we can mean a variety of things. In the most basic sense, a good building is one that physically serves its purpose (i.e., to physically encompass and support a hospital). From different perspectives, “good” collects more qualifications: the building’s function must be fulfilled attractively, efficiently, reliably, safely, and/or inclusively. Good buildings become even better when they serve their purpose and carry additional features, like full ADA accessibility, cultural significance, or LEED green building credits. Ideally, sustainable buildings and good buildings are the same. In reality, though, issues like short-term (rather than long-term) economic thinking can deepen the divide between “good” functional buildings and holistically good (and sustainable) buildings.
I argue that sustainable development can embrace the lessons and presence of historic buildings with positive environmental, social, and economic implications of historic buildings. In other words, why the best development solution is not destroying and replacing a historic building with a new and perhaps exemplary green building.
The UN’s 11th Sustainable Development Goal deals directly with the challenges facing cities (see also SDG 11 and SD: Cities). In recognizing the combination of exploding of urban populations (according to the Population Reference Bureau, 70% of the world population will be urban by 2050), and the humanistic value of heritage buildings and sites, the goal reads:
Goal 11: Make cities inclusive, safe, resilient and sustainable, including “strengthen efforts to protect and safeguard the world’s cultural and natural heritage.”
These four hallmarks (inclusive, safe, resilient, and sustainable) can be used to understand the various arguments in support of conservation and reuse of historic buildings.
There is a large body of work establishing the connections between heritage sites and humanity’s collective memory, or shared identity (see, for instance, a search of “collective memory” in the ICOMOS publications, or on Google Scholar). By definition, collective memory is an inclusive phenomenon. Historical sites are physical witnesses to shared heritage in the history and places that bind us together as humans. Our own stories can be shared and understood through physical places and spaces. Less abstractly, the acts of preservation, from documentation to regular maintenance, necessarily employ and involve entire communities (as in proven asset-based community development initiatives). ICOMOS guidelines exist for a project’s community engagement: for example, the Getty Conservation Institute recently completed a project on the participatory conservation of the Kasbah of Taourirt that relied on developing and utilizing local capacity in repair, technology, and documentation. Since heritage sites are rarely privately owned, we are all stakeholders of these resources and involved in decision making and use of these sites.
Safe
Vacant buildings are unsafe, and in many cities those vacant building are also historic. The correlation between increased crime and number of vacant properties has been established in the US. In fact, by using buildings that already exist within cities and reducing rates of vacancy in a city, historic buildings can both make cities safer and counteract urban sprawl (for example, see this excellent post on Sense and Sustainability). Safe cities, therefore, can be cities that embrace the potential and intrinsic value of their heritage buildings.
Resilient
In an age of urgent demand for resilient cities that can respond to increasing natural and man-made hazards (for example, rising earthquake, flooding, and fire risks in Seattle), we can learn invaluable lessons from heritage buildings that remain standing after 200, 300, 1500, 2000, or even 3200 years. The fact that these buildings have withstood assault on every front and remain stable speaks not only to the ingenuity of ancient builders but also to the resilience of these structures. Some ancient constructions intentionally dissipate earthquake loadings better than some modern buildings: compare the stacked drum columns of seismically active Greece to the monolithic columns of less-seismically active Rome. Because of their inherent resiliency, historic buildings do not necessarily require retrofitting and structural modification; like all buildings, historic buildings depend on regular maintenance for their longevity. Structurally safe and resilient historic buildings, with regular maintenance, can be more sustainable than new construction by eliminating the energy and waste involved in construction, use, and demolition of an entirely new building.
Sustainable
“Historic buildings are inherently sustainable.” So begins the Whole Building Design Guide, a knowledge portal for practitioners published by the National Institute of Building Sciences. The greatest advantage for historical buildings in the service of balancing sustainability and human development is, in fact, their inherent sustainability. These buildings can be adapted to a variety of new uses, whether the project is commercial, residential, or for public use. Not only does adaptive reuse of an existing historic building eliminate construction of a new building, it also eliminates accompanying construction and demolition waste. It is certainly important to consider the holistic energy use of buildings, from extraction, manufacturing, transport, and assembly of the materials in a building; to energy used by a building over its lifetime; to the demolition and disposal of its rubble. Recent life-cycle analysis (LCA) studies by the Preservation Green Lab compare similarly sized and used historic buildings to new construction options, concluding that most historic buildings can be reused with fewer environmental impacts than new “green” construction. Because they were constructed before interior climate control technology was developed, they are often equipped with efficient features instead. These include thick walls with optimal overhangs that trap winter heat during the day and release it at night and whose thermal mass helps the interior stay cool during summer months. Adaptive reuse of these structures can result in creative solutions, like Queen’s Quay and other projects in Toronto, that improve the sustainability and overall experience of a city. In looking at the “total energy” of buildings, in many cases the greenest building is one that is already built; embracing and using heritage buildings can be one of the best ways to make them sustainable.
Sustainable development for urban people and places naturally includes and necessitates preservation of our heritage sites. Furthermore, environmental steps toward sustainability simultaneously preserve both human and environmental health. This has a positive effect on our built heritage, reducing degradation mechanisms and threats to these sites, while improving environmental and social factors affecting our health.
Human development and sustainability, especially in an urban context, are balanced in the conservation and reuse of heritage sites. Residential and commercial buildings are responsible for 40% of the energy and 60% of the electricity used globally. Measures to increase building’s sustainability are in both the interest of human development and sustainable use of the world’s resources. In using a historic building, its lessons and embodied values can be preserved for future generations. The conservation of a city’s heritage sites is the conservation of humanity.
Isabel Morris is a 2nd year Civil Engineering PhD student in the Historic Structures Program. Her research is focused on using non-destructive methods, especially ground penetrating radar, to characterize materials for better conservation efforts around the world.