The GSA reaches new sustainable design heights with Building 48 in Colorado

Building 48 northwest basement rendering

Chris Whitcomb

August 11, 2023

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A pivotal design strategy moving forward will rely on the repurposing of existing building assets and infrastructure. The General Services Administration (GSA) has embraced this approach with Building 48, an exciting workplace project that sets new precedents for how the federal government will approach sustainable building design.

Building 48 entry canopy rendering

Previously a World War II Munitions Plant and most recently an aging National Archives and Records Administration warehouse sitting vacant on the Denver Federal Center, Building 48 is now reimagined as a leading-edge workplace for the Department of the Interior.  

While repurposing the building itself is a feat, the design is much more aspirational as it seeks to be LEED Gold, SITES Silver and both net zero energy and net zero carbon. Once open, the building will be operated by 100% renewable energy and serve as a zero emissions structure. 

Moreover, Building 48 seeks to achieve all these goals with standard systems essentially available to everyone. “This project is proof that standard systems strategically designed for optimal outcomes can lead to remarkable results,” adds Matt Bartels, CannonDesign’s Principal in Charge and Project Manager for the project. 


  • “Today, you’re really showing what ‘walk the walk’ looks like when we’re talking about climate change."

    Gina McCarthy Former U.S. National Climate Advisor
Building 48 north reception rendering

Numerous sustainable design strategies make this stunning adaptive reuse possible, including: 

  • Energy: The building will be a net-zero energy building that utilizes a 200KW roof-mounted solar array to charge an all-electric facility, cost-effective LED lighting along with high-efficiency heating and cooling systems (including electric boilers and air handlers) all designed to LEED Gold.
  • Operational carbon: Building 48 will also be net zero carbon. Its building operations will not generate carbon as it is a 100% electric building. There is no natural gas service to the building.
  • Embodied carbon: Reuse of the existing building structure and masonry skin saves enough carbon to drive an average car 43 million miles or power 3,300 homes for a single year.
  • Daylighting: Bringing daylighting to the building is a key tenet of the design. The project added 73 new windows that are 8’ x 10' in dimension. The design team also added 85 stunning skylights throughout the building.
  • Building site: Designed to SITES Silver certification, the landscape will feature adaptable trees, a pollinator garden and bioswales for water conservation to further connect employees to nature.
  • Adaptive reuse: This project reactivates a vacant, federally owned structure with historical significance into a modern workplace that now contributes to the Federal Buildings Fund.
  • Sustainable transit: There are 20 electric vehicle charging stations at Building 48, the largest concentration of EV stations on the DFC. The project has also installed the infrastructure to expand to 60 EV charging stations in the future.
Building 48 aerial exterior rendering

Beyond its breakthrough sustainable design, Building 48 also features numerous other interesting stories that help shape the project. We’ve broken those down below. 

Strategic workplace design

Sitting vacant, Building 48 had truly become an architectural “Frankenstein” of five buildings, building materials and design methodologies all cobbled together over a period of 30 years. Our collaborative team assessed all these unique approaches and set a vision for a unified solution that creates a dynamic community of interconnected neighborhoods along a boomerang building spine that’s enlivened by a forest of dappled light.

Building 48 boomerang diagram

Supporting the Department of the Interior’s Interior Business Center (IBC), the building unites hundreds of employees who provide acquisition, financial management, and human resource services to federal organizations.


  • “We're taking a vacant, underperforming building and transforming it into an adaptive, modern, energy efficient space to support the mission and business needs of the IBC. The intent is to transform the 1940s warehouse into a state-of-the-art office space that celebrates the mission of IBC while not impacting the environment.”

    Tanisha Harrison Public Buildings Service Regional Commissioner

A dynamic workplace strategy ensures these employees and their teams are supported by diverse spaces including conference rooms, touchdown spaces, collaboration zones, community lounges and more. A large open-seating atrium called “The Forest” is the main collaboration hub featuring a dynamic central stair, courtyard access, extensive daylighting and other key amenities.

Building 48 Forest rendering

Honoring its beautiful home state

Each of Building 48’s neighborhoods draw inspiration from the scenic wonders of Colorado. Wall colors, graphic treatments and other visual cues help celebrate iconic places like Mesa Verde, the Black Canyon of Gunnison, Red Rocks and Rocky Mountain National Park among others. Throughout the revitalized building, biophilic elements and connectivity to nature is wonderfully juxtaposed with the building’s exposed ceilings, duct work and concrete.

Design Build 

Also important to note, GSA Building 48 is being delivered via a collaborative design-build approach uniting our team with Centerre Construction. The design-build methodology accelerates decision-making, collaboration opportunities, project timelines and overall project outcomes. It’s a proven approach growing in popularity across regions of the United States and we’re excited to see the GSA leverage it with this project.