I’ve been at this a while now, closing in on two decades of experience with historic preservation and sustainable design. It’s been fascinating to watch these two disciplines move toward one another and start to intertwine. Much has happened over the years.
There was a time — not too long ago — when historic preservation and sustainability stood at opposite ends of the design spectrum, and attending a sustainability conference to advocate for the importance of preservation meant you would be part of a very small group. Likewise, speaking about sustainability to preservationists was heresy, as ‘those people’ were trying to ruin ‘our buildings’ with their new-fangled inventions.
Eventually, something happened akin to a scene in every cheesy romantic movie, where the two protagonists lock eyes from across the dance floor and rush toward each other — realizing that despite their different backgrounds and conflicting families, they have much in common and need to be together.
At this point, the preservation and sustainability communities began to recognize commonalities among the disciplines and how preservation should be part of a sustainable future. Champions of sustainability started talking about the importance of “avoided impact” — the environmental burden of new construction. This concept posits that one should consider the energy, carbon impact, and resource depletion required to construct a new building. In other words, avoided impact is the “embodied energy,” not expended because a structure was not built. In this context, embodied energy is the sum of energy it takes to create something, including the energy to extract, manufacture, ship, and install that item. What this means, in essence, is that historic preservation can conserve energy — and is, in fact, a sustainable approach to architecture.
When we preserve a building, we not only benefit from the avoided impact of new infrastructure associated with new construction, we also contribute to the vitality of the community. Researchers and demographers continue to learn how important dense, mixed-use neighborhoods are in creating and sustaining a vibrant, engaged community. From an environmental perspective, it’s also important to recognize how neighborhood configuration can have a profound impact on statistics like vehicle miles traveled (VMTs). Our older communities frequently provide the diversity of age, scale, and function required to support livable, walkable communities not found in newly planned, ‘standard’ developments. Of course, this shouldn’t be news to us — Jane Jacobs wrote about this concept more than 50 years ago in her groundbreaking book, The Death and Life of Great American Cities.
Interestingly, as the sustainable community started paying attention to preservation, the preservation community began to recognize that our older buildings were green before green was around. Why?
Put simply, older buildings were designed for specific climates and low energy budgets. Before the introduction of central air conditioning, electric illumination, and other inventions that enabled us to use technology to isolate us from natural forces, designers and builders had to know how to take advantage of fundamental building physics to condition our buildings because technologies to overcome these challenges were either extremely expensive or simply didn’t exist. Modern concepts of sustainability, such as solar orientation, layer stratification, daylighting, and thermal chimneys, really are the rediscovery of traditional design elements.
This isn’t to say, however, that modern technology hasn’t proved useful in preservation projects. We’ve seen advancements in energy modeling that enable us to understand where the primary sources of heat loss/heat gain occur — and to more effectively design to minimize heat transfer. In many of our adaptive use projects at Marks Thomas, we’ve found it far more effective to provide more insulation in roofs rather than the walls of historic structures. This, in turn, better preserves the integrity of the historic fabric, while increasing the energy performance of the building.
As we move forward, I’m eager to see how the overlap between preservation and sustainability continues to grow and deepen. If you have a historic preservation or sustainable design project you’d like to discuss, we can help. Get in touch to start the conversation.