A design/build renovation of the Byron G. Rogers Federal Building in Denver focused on modernizing the interior—offering more sunlight, larger offices, better wayfinding, and an innovative heating system. The historically significant formalism style of architecture remains. Library of Congress
A comprehensive renovation of the Byron Rogers building in Denver updates the energy performance while preserving the classic, formalist facade.
May 13, 2014—People passing by the Byron G. Rogers Federal Building at 1961 Stout Street in downtown Denver will have very few cues that the building is in the final stages of a dramatic renovation. The building, completed in 1964, is considered a historically significant example of the formalism style architecture. It anchors a federal district that includes a courthouse and customs house.
The U.S. General Services Administration (GSA), which owns the building, undertook the renovation project with the goals of preserving the exterior’s character and precast aggregate panels, while creating a modern, functional interior to compete with other state-of-the-art office space available for lease in the Denver area. The project also met high energy-efficiency and sustainability goals.
“From the outside, it looks very similar. The inside is much lighter and brighter,” says Aimee Rowbottom, AIA, LEED-AP, a director of project management for HOK, the St. Louis-based architecture and engineering firm that served as the design architect on a design/build team led by Mortenson Construction, of Denver. Bennett Wagner & Grody Architects, of Denver, served as the architect of record.
“It’s almost eligible for [listing in the National Register of Historic Places] in terms of its age,” Rowbottom says. “So our fundamental strategy was to prepare it for the next 50 years of its life by designing a high-performance, green building interior, and leveraging the existing skin as it is.”
To achieve significant energy savings, the project increased the structure’s insulation, but from the inside so as to preserve the facade. The team comprehensively upgraded all major building systems: mechanical, electrical, plumbing, lighting, and fire protection. A chilled-beam system uses moderately heated water to control the interior temperature. The system captures heat from a variety of sources, including the solar gain of the windows and the exterior panels—as well as from such everyday office fixtures as computers and lighting—and stores it in large thermal tanks in the basement.
“Mechanically, the strategy was to leverage the thermal mass of the building, especially the west-facing facade, to collect the energy from solar gain and store it in tanks in the basement. And then, when heat is needed, warm water from these tanks is piped back up through the building to efficiently condition the spaces. We are using the mass of the building [for] thermal capture,” Rowbottom explains. The RMH Group, Inc., of Lakewood, Colorado, served as the mechanical and electrical engineer on the project.
One of the key engineering challenges of the project was to retrofit the structure to meet updated Denver seismic codes and to meet GSA requirements for progressive collapse and blast mitigation. “We went in behind the existing skin of the building and created three levels of an internal truss frame,” Rowbottom says, adding that several bays within the structure were bolstered as well. Large steel beams were brought in through the window openings, placed behind the exterior panels, and welded into a cohesive truss.
The project included the replacement of the existing windows with units carefully designed to match the appearance of the original fenestration while dramatically improving the thermal performance of the facade.
That proved to be less a challenge than matching some of the interior marble. During the project, the team discovered some original marble in the basement, however, that was then placed in more visible areas.
It was no easy feat to create a modern office environment within a historical structure. The floor plans HOK developed eliminate, as much as possible, the closed, perimeter offices that blocked the flow of natural light into the structure. In cases in which perimeter offices are required, glass interior walls allow the daylight to flow through. Glass was also employed in the framing of the walls that surround the elevator core lobbies.
“That also helped with our wayfinding strategy,” Rowbottom explains. “Upon arrival to a floor, when you come off the elevators, you know when [you] I look left or right [you are] going to be able to orient [yourself] to the direction of travel by the light coming in through the glass. Conversely, when you are leaving and come down any of the interior corridors and you see the light at the end, you know that you’ve reached your point of destination.
“The footprint, in laying out interior space, is challenging,” Rowbottom says. “It’s wider in the middle and tapers to the edges. And then it has quite a few interior columns. Working with those parameters in laying out a more modern and open work space, I would say, was the biggest challenge.”
The $154-million project was funded by the American Recovery and Reinvestment Act of 2009. Federal agencies housed in the building were temporarily relocated and have since returned. Some additional federal agencies that had been leasing commercial space in Denver are moving in as well.
The design team is working with those agencies to develop the best floor plans for their needs, offering templates and a palate of sustainable materials from which to choose. The project is currently on target to be complete later this year and to achieve a minimum silver rating in the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) program.