north tower, which also includes cupola and lantern with decorative elements, using approximately 115,000 pounds of copper on the overall project.
Flat roof areas on the 10th and 12th floors were replaced with a SBS modified bitumen roof system that originally was felt and asphalt over a cement decking. Additional layers had been applied over the years. The slate roof of the main portion of the building had been replaced in 1973-74. That area rises to a copper coping at a flat roof over the center of City Hall.
“It likely was the most challenging project we’ve ever worked on,” said Greg Johnson, FJAC operations manager for the renovation. Contributing to the challenge was the multi-year timeline, the complexity of installation, coordination with FJAC’s Canadian copper fabricator for some of the replacement pieces, the need to arrange schedules with several other trades, access to heights,
and the working conditions 300 feet above ground.
As a National Historic Landmark, original elements of the building had to be maintained or restored, including ornate and decorative panels that were worn out or missing.
While original drawings and plans facilitated replacement of architectural elements, installation wasn’t always easy.
“When you work on a building that’s more than 100 years old, nothing is perfectly square or round,” Johnson noted. “What works on paper plans doesn’t always work in the real world. The City Hall project required numerous field modifications.”
The weather also was an issue for the crews working hundreds of feet above ground. “Other than June, July and August, it was windy every day up there,” Johnson said.
An on-site hoist allowed some materials to be lifted to the roof sections, but some areas were only accessible via interior elevators and stairwells, and the hoist was removed from the job site before FJAC’s work was done. |