From the sidewalk facing the main entrance, the three-story federal building in downtown Grand Junction, Colorado, looks much as it did in 1918 when it first opened. Turn the corner and look up at the roof, however, and a more modern structure comes into view. It is a canopy that supports the bulk of a 123-kilowatt solar array, one of several new green features added to the 41,560-square-foot building during a recent $15 million renovation and modernization project led by the General Services Administration and funded by the American Recovery and Reinvestment Act. The Wayne N. Aspinall Federal Building and U.S. Courthouse is not only LEED Platinum certified but also aims to be the GSA's first net zero building listed on the National Register of Historic Places. Cleveland-based Westlake Reed Leskosky served as lead design architect for the project, completed in 2013.
Photo © Kevin G. Reeves
Named for a former Colorado congressman, the Aspinall is a Renaissance Revival structure that features a limestone facade, arched first-floor windows, and a colonnaded parapet running along the perimeter of the roof. Designed under the direction of James Wetmore, who led the U.S. Treasury Department's Office of the Supervising Architect from 1915 to 1933, the building was expanded in 1938 and now houses nine federal agencies.
Over the years, much of the interior had been clumsily modernized. The gracious main lobby, originally a post office, was partitioned, and throughout the building, drop ceilings were added to hide ductwork.Wood floors were concealed by carpet. A WPA-era mural—The Harvest, by Louise Emerson Ronnebeck—that hung over the postmaster's office door in the lobby was removed for cleaning in 1973 and went missing for nearly 20 years. When it finally returned to the building in 1992, it was sequestered in a stairwell.
Architects from Westlake Reed Leskosky originally wanted to put a much larger solar canopy on the roof, one that would be clearly visible from street level on all sides of the building. "It was bold," says managing principal Paul Westlake. "We wanted it to be a symbol of energy independence." But when representatives from Colorado's historic preservation office saw the plans, they asked that the canopy be scaled back to preserve the historic view of the facade.
"It forced us to try to figure out how to make the historic building itself far more efficient than we had originally planned," Westlake says, "because we had lost a significant amount of alternative energy. It was a problem, but also an opportunity."
The firm, working with design-build contractor and architect of record the Beck Group, of Dallas, had already planned to add a number of sustainable elements, including ventilation-only ductwork, energy-efficient lighting fixtures, interior storm windows with high-performance UV control film, low-flow plumbing fixtures, and rigid roof insulation with an average thermal resistance of R-35. But to get to net zero, they needed to do more.
Serendipitously, Westlake and his colleagues discovered that the building's original 3-foot-thick walls included a 2-inch layer of terra-cotta covered by a skim coat of plaster to form the interior surface. By removing the terra-cotta and replacing it with foam insulation, they were able to meet some sustainability goals without losing any square footage. And with the addition of a 32-well geothermal system for heating and cooling, they reached the net zero goal.
Meanwhile, the architects restored many historic features throughout the building. The lobby now displays much of its original grandeur, including those arched windows, an interior arched colonnade, decorative column capitals (all long obscured by the drop ceiling), and a marble-bordered terrazzo floor. The Harvest has been returned to its proper location.
Roger Chang, Westlake Reed Leskosky's director of sustainability, says the building demonstrates that it is possible to modernize a nearly hundred-year-old structure while retaining its original character. Energy efficiency and preservation, once thought to be incompatible goals, can be quite complementary. By reducing demand for energy, he says, the need for intrusive and unsightly mechanical systems can be minimized. For example, the new variable refrigerant-flow heating and cooling system employs a 1-inch water pipe that moves the same amount of energy as a 14-inch-square air duct. (Goodbye, drop ceilings.) And natural lighting—particularly in a place like Grand Junction, where the sun shines more than 245 days a year—was embraced by placing workstations near windows.
"The Aspinall building," Chang says, "has become something of a poster child for combining sustainable design with historic preservation." In April, the American Institute of Architects' Committee on the Environment named the Aspinall building one of the top 10 national green projects of 2014.