Olivia Leingang joined Hennebery Eddy’s Bozeman studio as a summer design intern, participating in the firm’s robust internship program that includes conducting an in-depth research project. Olivia graduated with a Bachelor of Science in Architecture from North Dakota State University in May 2025 and is now pursuing a Master of Science in Architecture, also at NDSU. Read more from our 2025 internship cohort and all our past intern research projects here.
Existing Buildings vs. New Construction
With climate change reaching unprecedented levels and causing nearly irreversible damage to our planet, architects must take action to design our built environment responsibly and reshape the trajectory of our future. Currently, the built environment accounts for 42 percent of global CO2 emissions. To create change, architects and engineers must not only advocate for environmentally friendly designs in new buildings but also prioritize repurposing existing structures. By saving materials, avoiding demolition, and reducing construction, reusing existing buildings is almost always more environmentally friendly than building new.
According to the AIA, renovation and adaptive reuse projects typically produce between 50 and 75 percent less embodied carbon than new structures.
Environmental Benefits of Adaptive Reuse
As Carl Elefante, a former president of the American Institute of Architects (AIA), famously stated, “The greenest building is the one that is already built.” This perspective is supported by Living Future, which indicates that brand-new energy-efficient buildings can take 10 to 80 years to offset their construction’s climate impacts. In contrast, reusing buildings can save between 4 and 44 percent in environmental impact, largely due to the embodied carbon in the existing materials. According to the AIA, renovation and adaptive reuse projects typically produce between 50 and 75 percent less embodied carbon than new structures. As the industry increasingly focuses on operational efficiency, it’s anticipated that embodied carbon could surpass operational emissions, potentially becoming the largest source of carbon emissions in the building sector by 2030. Reusing buildings significantly cuts down this number and creates a solution to this issue.
Achieving Net-Zero in Adaptive Reuse Buildings
Reusing existing buildings is beneficial to the environment because it helps save embodied carbon, but to successfully reach net-zero energy and carbon in adaptive reuse projects, there are several factors architects must consider. The following design framework I created outlines six key categories to focus on when pursuing net-zero goals in adaptive reuse. Each category includes various subtopics that should be addressed to enhance a project’s success. By utilizing this framework to guide project goals and development, it is possible to create a net-zero adaptive reuse building.
A design framework for pursuing net-zero energy in adaptive reuse projects.
Case Study: Multnomah County Library Operations Center
Hennebery Eddy’s design of the Multnomah County Library Operations Center in Portland serves as an exemplary case study in sustainable and adaptive reuse design. The project transformed what was once a Safeway grocery store into a state-of-the-art, LEED Gold-certified, net-zero energy operations center, relocating “the beating heart” of the Multnomah County Library system to a more centralized location. The project scope consisted of demolishing part of the existing structure and adding a two-story addition. Despite the partial demolition, 94% of construction and demolition waste was diverted, preventing approximately 3,700 tons of waste from entering landfills. By reusing the existing structure and diverting waste, the Operations Center achieved a 66% reduction in embodied carbon compared to a new construction baseline.
The design reused the existing Safeway structure while adapting it to fit the needs of the new Operations Center, upgrading the building envelope to improve thermal performance and increase needed daylight. Additionally, the building was seismically upgraded to ensure occupant safety, and wood from the existing structure was repurposed for stair treads, benches, and shelving in both the Operations Center and the new Northwest Library.
The Operations Center features 602 solar panels on its roof that generate more than 353 megawatt-hours of energy annually, which is enough to power 33 homes for a year. It is the first building to comply with Multnomah County’s Fossil Fuel-Free Buildings resolution, setting a precedent for future projects. Hennebery Eddy also collaborated with the Portland Street Art Alliance and the Regional Arts and Culture Council to display nine murals created by local artists, both inside and outside of the building. The facility houses more than 500,000 collection items that serve the county, and the project achieved a 36% COBID-certified subcontractor and vendor utilization under general contractor Fortis Construction.
Overall, the Multnomah County Library Operations Center exemplifies how reusing part of a building can contribute to achieving sustainability goals. It demonstrates that adaptive reuse projects do not have to be constrained by the original building’s shape or size, and that adaptive reuse and net-zero design can successfully coexist.
Conclusion
Embracing, seeking out, and setting high goals for adaptive reuse projects is a vital step toward creating a more sustainable future. By rethinking existing structures instead of opting for new construction, architects can significantly reduce carbon emissions and promote smarter use of resources. To guide adaptive reuse projects through their development toward becoming net-zero, the design framework I created can be a useful tool by outlining essential components to consider during project development. As the field continues to evolve, recognizing the value of existing buildings and their potential for renewal and innovation will lead to a more resilient future.
Internship Experience
My summer internship at Hennebery Eddy was an invaluable experience. I am very lucky to have worked at a firm that aligns with my values and designs responsibly for communities and the environment. Throughout my internship, I attended numerous site visits, worked on various phases of multiple projects, completed a three-month long research project, and even got to travel to the Portland office for Intern Week. On top of all everything I learned, I was able to work with great people who truly want to see me succeed. I’m very excited to take what I’ve learned this summer and apply it in my future.
Research Sources
- Architecture2030.org
- “The Greenest Building: Quantifying the Environmental Value of Building Reuse” report by Preservation Green Lab
- Carl Elefante, author of “Going for Zero”
- “Building Reuse: A Proven Climate and Economic Strategy” by AIA and National Trust for Historic Preservation
- “A Wholistic Approach to Carbon Emissions: A Case for Adaptive Reuse” by Daniel Kinnett, via Mile High CRE