The building-within-a-building solution ensured that the exterior brick walls were left untouched, except in places where structural elements were needed for support. In addition, a number of elements were incorporated to provide employees and visitors a glimpse of the facility’s history. The original single pane windows in the brick walls, which were rotting out, were replaced with metallic double pane windows of identical design.
A large, open lobby enables everyone to get a feel of how the building looked in the past. An Interurban street car that ran all the way from Denton to Waco sits in the lobby to remind visitors of its heritage. All the historic materials salvaged from the building were preserved, and original signs and fire doors were reincorporated.
“As the project progressed, we modified the design a few times to make sure that we didn’t affect the original structure,” said Greg Read, AIA, principal of Brinkley Sargent Architects. “We took every opportunity to showcase the existing structure throughout the facility.”
Greening the Building
In keeping with DART’s commitment to sustainability, the TRACK team was also tasked with achieving the highest possible LEED certification. Accomplishing this goal in a nearly 100-year-old building made the task more challenging.
As a first step, the project team remediated the site scarred by years of neglect. Nearly 90 percent of all construction waste from landfills was diverted during abatement and demolition. The heat-island effect in the roof and parking lot was reduced significantly through the use of high-solar reflective materials. Preferred parking for fuel-efficient and low-emitting vehicles further enhanced the sustainable character of the site.
The building-within-a building solution created an interstitial air space that helped alleviate the lack of insulation from the existing brick exterior. An under-floor air distribution system, another novelty, was installed on the second and third floors, which allowed cooling air to be supplied at a warmer temperature than an overhead distribution system, saving substantial energy in the process.
To take full advantage of available natural light, daylight-responsive lighting controls were installed within 15 feet of exterior windows or skylights. Efficient lighting fixtures reduced the lighting power density by as much as 36 percent. Furthermore, Energy Star-rated equipment and appliances equal to 98.4 percent by rated power were used throughout the facility.
Emphasis was also placed on maximizing the use of sustainable materials and resources. More than 20 percent of the total materials were manufactured using recycled content. Also, 34 percent of the materials were manufactured within 500 miles of the project site, and more than 50 percent of the total wood-based building materials were harvested from FSC-certified forests.
The building’s proximity to the Illinois light rail station, the availability of five bus lines within a quarter mile, as well as newly installed bicycle storage and shower facilities, provided a number of alternative transportation options. Other sustainable features implemented included water-efficient plumbing fixtures, low-VOC adhesive and sealant products, CO2 sensors in densely occupied spaces, as well as a green housekeeping system.
“What makes this project so different from other adaptive reuse projects around the country is its sustainability,” said David Powyszynski, AIA, senior vice president of Aguirre Roden Architects. “The fact that this is the first publicly owned historic building to achieve LEED Platinum certification is a matter of great pride for us.”
Other Project Challenges
The complexity of the project presented a number of additional challenges. Foremost among them was the discrepancy in available space to satisfy the project’s requirements. The program for the police headquarters called for a facility of about 65,000 square feet, while the existing building had a footprint of only about 35,000 square feet. The main section of the building, the former train maintenance area, consisted of one long, narrow space for the entire length of the building and had a vertical clearance of only 30 feet from floor to bottom of the historic steel roof trusses that spanned the space. An area almost half the length of this main space had a similar vertical clearance. The other two sections of the building, which were added at a different time in the building’s history, lacked sufficient clearance to fit more than a single floor.