DETROIT - More than a million square feet. Five thousand windows. No air conditioning. That was GM's former world headquarters.

The former General Motors Building, now offices for the state of Michigan.
DETROIT - More than a million square feet. Five thousand windows. No air conditioning.

That was the former world headquarters for General Motors Corp. before a two-year, $126 million renovation of the 80-year-old building was completed in November.

Although the historic structure was much loved by architects and GM workers for its ornate, arching ceilings, marbled hallways and limestone-covered facade, it was far from an ideal working environment. While well-preserved, virtually everything - from elevators to electricity - in the mammoth building was outdated. Steam radiators provided all heat. During the summer, 1,860 window air conditioners, combined with hundreds of spot-cooling devices, attempted to keep employees comfortable, often with little success.

In 1996, GM officials decided it was time to move to a new location. The state of Michigan then announced it would be taking over the GM Building to consolidate the offices of thousands of employees spread throughout the region, but not before a major overhaul of the structure. Most of the former offices, except for some mahogany- and marble-inlaid suites on the upper floors, would be gutted. A central HVAC system would be installed. All in about two years.

"This was a complex project on a very tight timetable," said John Steinhebel of Barton Malow Co., the general contractor for the project.

The GM Building under construction in 1919.

A landmark

Plans called for the landmark building to be modernized while keeping as many of its historic elements as possible. The massive, urban Beaux Arts-style GM Building dates back to 1919. Well-known industrial architect Albert Kahn, who had designed factories for automakers Ford, Chrysler and Packard, built what was then the largest office complex in the world.

He covered the exterior of the 15-story building in fine-grained limestone, with unbroken fluted piers that lead to a colonnaded crown and ornate, barrel-vaulted main entrances. The ceiling of the first floor rose 70 feet and was decorated in several classical themes and styles.

Eight wings radiated from an elongated central block towards the front and back of the building. The wings were designed by Kahn to allow natural light in and air to circulate in the offices, since artificial lighting in the 1920s was limited and air conditioning was nonexistent.

The structure was originally to be called the Durant Building, named after GM founder William C. Durant. Although Durant had been forced out of GM by the time the building was finished, the letter "D" was still engraved in several places.

At one time, the 2,000-office complex contained an automotive laboratory, two swimming pools and a 19-lane bowling alley.

One thing the GM Building never had, however, was ductwork. And making and installing it was such a big job that three sheet metal contractors were needed: Ventcon Inc. of Allen Park, Mich., Cooney Engineering of Oak Park, Mich., and Pontiac, Mich.-based Limbach Co. The contractors worked throughout the fall of 2001 and spring of 2002.

Brad Grafmiller, Ventcon project manager, said his company's $2 million contract had workers fabricating and installing 22,000 feet of mostly rectangular, low- and medium-pressure duct. It would be used on the second, third and fourth floors.

New walls are going up as the state of Michigan takes over the former GM Building. Photo courtesy of Limbach Co.

No time

week down there for quite a few months."

Ductwork, as well as new piping, would have to be installed between the original plaster ceiling and the new drop ceiling, in a space less than 4 feet deep. Grafmiller said all contractors had difficulty working in this "pinch" area.

"We just jammed it in as tight as we could," added Darin Smith, Limbach Co. project manager. Limbach's $6 million contract included six of the upper floors.

Work was often slow, due to the age of the building, Smith said. Freight elevators regularly broke down and the discovery of asbestos meant that work could stop in an area for days while it was removed.

Chris Kjolhede, president of Cooney Engineering, also said space limitations were the biggest obstacle his workers faced installing the 200,000 pounds of duct the company had fabricated. Cooney worked on four of the building's middle floors and two floors of a concourse below ground where coordination with other construction workers was "quite a nightmare," Kjolhede said.

Still, Kjolhede said he is not complaining.

"That's typical," he said of the coordination issues. "For us, it was a pretty simple job."

The ductwork Limbach, Ventcon and Cooney were installing would tie in to packaged, water-cooled air-conditioning units from Trane Co. with variable air volume- (VAV) conditioned air distribution. Architects from Detroit-based Albert Kahn and Associates - the same firm that originally designed the building - and Barton Malow staff decided a typical central chilled-water plant was impractical for the building, because of a lack of space for the plant and the necessary piping to distribute the chilled water.

Trane SCWBs, rated at 65 tons each, were chosen. The designs called for 68 units, with four on each floor in the main building and six units in the annex. Four rooftop cooling towers would provide water. Steinhebel visited the Macon, Ga., facility where the units were made before OK'ing them.

"I wanted to talk to the factory people to see how the units were assembled," he said. "We had a tight delivery schedule and little time to correct possible problems with the units, so I needed to be sure."

John Piccolo, project manager for TrizecHahn Development Services, which oversaw the job for the state, said the building's existing 10-inch water risers were adequately sized to handle the condenser cooling water for the new units.

"The risers themselves were in pretty good shape," Piccolo said. "We chemically cleaned them and installed new strainers and they have performed real well. Not having to replace that piping has meant a real savings."

Space was at a premium in the new building. Ductwork, piping and wiring all had to be installed in a very confined space. Photo courtesy of Limbach Co.

Dual-design duct system

The new duct system is a dual design with air for ventilation distributed throughout the building. Air comes from the self-contained units to 1,400 VariTrane VAV terminal boxes. Perimeter heating is comes from a system of radiators and convection cabinets. A Trane Tracer Summit control system allows temperatures to be adjusted throughout the building. Office areas now have wired thermostats controlling the VAV boxes, so tenants can adjust the temperature themselves.

The building cool system runs year-round, due to the internal heat loads in the office areas. Mechanical cooling is used during the summer.

The rest of the building was completely updated with new fiber-optic telephone lines, high-speed Internet access, new carpeting, acoustical tile, energy efficient lighting and architectural dividers.

The building was renamed Cadillac Place, in honor of the French explorer Antoine de La Mothe Cadillac, who founded Detroit in 1701, and the luxury car brand for which the building's former tenant is known. A 1919 Cadillac is on display in the lobby, which retains its original appearance.

Today, the building houses 2,000 state workers and the local offices for the state attorney general and other state departments. The state's Court of Appeals is on the 14th and 15th floors.