Adaptive Reuse – Part 1 Environmental and Social Rationale

Transformation is the opportunity of doing more and better with what is already existing. The demolishing is a decision of easiness and short term. It is a waste of many things—a waste of energy, a waste of material, and a waste of history. Moreover, it has a very negative social impact. For us, it is an act of violence.

• Anne Lacaton, Pritzker Prize Announcement

In 2022, the AiA reported that the percentage of adaptive reuse projects compared to new construction had reached 50%, or approximately half of all architectural billings in the United States. In an interview with the AiA’s Chief Economist, Kermit Baker, Baker argued that this represents an historical trend in which the proportion of adaptive reuse projects has steadily increased since 2005. He also stated that he expects this trend to continue for the foreseeable future.

The Pritzker Prize was awarded to French firm Lacaton + Vassal in 2021. Award literature emphasized their work in adaptive reuse in a manner that reflects the refocusing away from new construction and to processes of renewal, renovation and reinvigoration studied by the AiA. For Lacaton + Vassal, reimagining a space not only represents a distinct design challenge, but it also respects ecological and social imperatives better than new construction.

As the brief quote from Lacaton + Vassal’s Pritzker Prize announcement cited at the beginning of this article shows, the justifications for adaptive reuse fall into four general categories: conservation of energy, materials, history, and social fabric.

Energy + Materials

The differentiation between energy and materials is a subtle one since materials themselves both embody energy and inform the energy performance and profile of buildings. Processes of extraction, refinement and production all require energy, and all have their own significant ecological impacts (including environmental and habitat degradation and waste), with certain forms of resource extraction and processing being more energy intensive and polluting than others. For example, in 2011, iron and steel production accounted for 31% of all material emissions, and cement, lime and plaster production accounted for 24%, while wood products only accounted for 9%.

Meanwhile, the largest carbon footprint of materials in downstream application was that of cement, lime and plaster in construction, which accounted for 2.5 GtCO₂e (gigatonnes of equivalent carbon dioxide) in 2011, with the use of iron and steel products in construction being the second highest at 0.75 GtCO₂e in 2011. The net consequences of natural resource depletion, ecological erosion and environmental pollution associated with contemporary construction practices are so significant that architect Charlotte Malterre-Barthes has called for a global moratorium on building until international environmental standards for construction are established.

According to a UNEP (United Nations Environment Programme) and IEA (International Energy Agency) report, building operations and construction represented 36% of global energy consumption, and 39% of energy related carbon emissions in 2017, with gains in energy efficiency offset by the embodied energy of new construction and increases in new construction associated with increased global wealth and population. Embodied energy associated with new construction can account for up to 50% of a building’s energy profile depending on the longevity of the building and the building’s lifecycle profile (the longer a building is in use, the lower its embodied energy profile is proportional to its operational energy).

As buildings have become more energy efficient, embodied energy has assumed a greater proportion of the ecological and environmental cost of the built environment. New construction not only requires much larger quantities of materials, but in instances where demolition is required, the overall environmental impact of new construction includes the embodied energy of the materials of the existing building(s), as well as the environmental impact of their removal and disposal. Even where there is building material reclamation, the overall impact of new construction in such instances is significantly higher than that of reuse (in some instances as much as 46% higher).

Even highly efficient newer buildings can take up to 80 years to offset the embodied energy associated with their construction. Given that the average age of contemporary commercial buildings is only approximately 40 years, this means that most buildings have not yet offset embodied energy associated with construction even in instances where the building is highly efficient. In instances where the building is not efficient, the issue is only compounded. The comparatively high embodied energy and environmental cost of material production for new construction thus provides both an energy and a material incentive for the adaptive reuse, renovation, and/or upgrading of existing buildings, especially where demolition becomes a contributing factor to the energy profile of a new building.

History + Social Fabric

Like energy and materials, history and social fabric are difficult to disassociate, since a building warps the social fabric into which it is stitched, and the longer it persists, the deeper its impact (positive or negative). Unlike energy and materials, the positive or negative contributions of existing structures to the history and social fabric of a place is difficult to quantify, and more subjective. It could fall under the rubric of “character,” and as such should not be totally discounted, as character can be a significant contributing factor to place-making and, as such, to social and behavioral norms of a given environment. It can also be instrumental for economic redevelopment.

Every city has a different sensibility, and within a city, every neighborhood has its own rhythm and texture, like a quilt patched together from different sources. The built environment informs the character of a place through both spatial organization, infrastructural amenities and material (tactile) sensibility. In instances where each contribute to the health, wellbeing and happiness of local residents, and can be used to enhance the sense of place, of belonging, and of cultural cohesion, adaptive reuse can embrace history to improve the social fabric.

There is a wealth of case studies that show how imaginative and successful reintegration of derelict structures can radically improve habitation and socially reactivate spaces, including the Highline by Diller Scofidio + Renfro, Powerhouse Arts by Herzog + de Meuron, or the Tin Building by SHoP Architects, not to mention the many projects for which Lacaton + Vassal won the Pritzker Prize. Thoughtful interventions that balance respect for context and character with innovation and rejuvenation can transform even problematic places into socially engaged environments.

Measure + Means

While the architectural profession as a whole is becoming more conscious of the ecological and environmental consequences of construction, and the historical and social implications of preservation, there is a tendency to make broad assumptions about the value or problematics of different paradigms. As a report from the National Trust for Historic Preservation shows, adaptive reuse is not always environmentally the better option; converting certain buildings to new uses can prove as ecologically costly as new construction, and in some instances even more so. Similarly, buildings like Minoru Yamasaki’s Pruitt Igoe housing development may have so many organizational, social and historical challenges that remediation from the social and historical perspective becomes prohibitive.

The problem with making blanket claims about the value of adaptive reuse compared to new construction is that it elides the vast diversity of project types. An adaptive reuse project that uses energy intensive materials, and does not address potential issues with operational energy can be significantly more environmentally problematic than a new building that addresses embodied carbon and operational energy. Furthermore, not every building is worth saving; endemic structural and infrastructural issues, poor design and other issues may frustrate efforts to reuse a structure in any meaningful way, and just because a building is old doesn’t mean that it has any inherent historical or cultural significance, or at least not enough to support preservation.

Yet, in a world plagued by supply chain constraints and labor shortages, where timeline can impact occupancy or the financial sustainability of a project, adaptive reuse can be an imaginative, ecologically and socially sensitive option. It is also only one of several options that might be employed to revitalize a building, including conversion, refurbishment, renovation, rehabilitation, and retrofitting, all of which have their own distinct design challenges and advantages, and all of which exhibit different scales of intervention in a preexisting condition. It is important to understand the different tools available to both improve the embodied and operational energy of construction, as well as the social viability of a place.

Return for Part II – Building Lifecycles and Service Upgrades!

In next month’s Part II to this article, we will discuss the lifecycles of building services, and potential means and methods for future-proofing buildings by ensuring access to critical infrastructure and providing up-gradable services that can adapt with technological and material transformations.