The issue of mechanical and electrical distribution proved a particular challenge, given that "out of 19 floors, there are actually only five floors that are basically the same floor plates," says Hohmann.

Over a period of months, Ebersoldt worked with team members to devise no fewer than 85 different floor plans for apartments. In plotting vertical and horizontal runs for M/E/P systems, "We had lots of offsets we had to deal with to avoid impacting historic areas," Hohmann says.

The issue was no less acute in the historic arcade, where one source of heating derives from the basement, where a network of heat pumps distribute air through ductwork concealed by decorative metal grilles near the space's base.

Fieldwork has proceeded smoothly due to the high accuracy of an initial survey Paric performed of existing conditions. To ensure final documents for the project were as accurate as possible, the firm laser-scanned the entire facility, then overlaid resulting measurements on documents generated by Ebersoldt. "As a result, our documents were much more accurate than had we relied solely on our drawings," Hohmann says.

Nevertheless, Paric and crews of up to 175 negotiated complex logistics at the outset. Because elevators weren't operable at the onset of sitework, crews and materials relied on a pair of temporary hoists to reach their destinations until earlier this year, when a pair of replacement elevators came on line.

The site also afforded no space for storing incoming materials and systems, prompting complex scheduling and planning to ensure the availability of buck hoists. "It really amounted to a full-time job," says Hugeback. Working from the top down, "It was a matter of installing parts as they were received."

Work proceeded in two shifts, with a third periodically added to facilitate chemical cleaning of exterior masonry when other trades were off site.

With no elevators in place, a helicopter was deployed to deliver pressurization fans for elevator shafts atop Arcade's roof, an undertaking that involved coordinating with local police and air traffic control, in addition with transportation authorities to facilitate street closures. Weather stalled the first effort. The second, performed on a weekend, was accomplished in a single day, Hugeback says.

For Hohmann, the project represents a second crack at an architectural gem that fascinated him since boyhood. "The first time I visited the Arcade I was 8," he recalls. "It was the place to shop in downtown St. Louis, and I was absolutely awed by its architecture."