Cutting Edge Passes for Classic

“What you don’t see in pictures of this renovation is what went into the planning, and the challenge of the unknowns of an older structure,” said Tomoo Fujikawa, architect on the project. Fujikawa is principal and president of the Chicago architectural firm Fujikawa Johnson Gobel, the firm responsible for the design of the 1997 east addition to the original CBOT building.

“It’s one thing to open up a building of recent construction and it’s another to open up a building that’s over 80 years old,” Fujikawa noted. “Sometimes you find surprising things in the walls, floors or ceilings—things that may work in your favor or may not.”

One key element working in the restorers’ favor was the original 85-year-old floors in traditional sand cushion terrazzo in the CBOT’s historic first-floor lobby.

Its striking art deco pattern of circles, arcs and angles is now restored as the distinctive public face of the building’s interior, its presence expanded and complemented with the addition of a 3/8-inch epoxy terrazzo floor. Indistinguishable from the original floors, the new floor is as opulent as the old classic terrazzo, which in turn still looks as fresh as the new.

“The beauty is that standing there I imagine most people don’t realize it’s new,” reported Fujikawa. “It looks perfectly natural.”

The behind-the-scenes persistence and care that went into integrating today’s materials into the building’s history using today’s construction methods is now evident only in the story of how restorers created the illusion.

“The process of matching the complex historic colors and aggregates with today’s materials was a real challenge,” Tucci reported.

To develop color formulas, contractors began by removing small sections of the historic floor. They brought the pieces back to their workshop and stripped off any wax, sealants or buildup to clearly reveal the true colors. Then began the process of finding a blend of epoxy and aggregates to recreate the colors of the pieces.

Because the original stone aggregates were mined from a quarry over 85 years ago, matches were no longer available as mining has continued. Duplicating the appearance of the original floor required mixing different aggregates to mimic the originals. While beiges and blacks are relatively simple to match, Tucci said, the green tones of the original art deco floor presented a particular challenge. The process of trial-and-error sometimes took 15 to 20 rounds of samples to achieve a ideal match.

“These are natural products harvested from the earth,” Tucci explained. “It’s hard enough even a couple of years later to match stone from a quarry, let alone when this much time has passed. The slight natural variances of terrazzo are actually an asset—no two floors are exactly alike. But getting a perfect match is challenge because you’re dealing with ‘Mother Nature.’”

For a successfully completed project, Fujikawa reported that the entire team worked well together to realize the owner’s vision, with every element playing its role. Behind-the-scenes coordination of parts and pieces brought them all together as a whole, he said.

“Terrazzo played its role well; it was certainly an economical material with lots of flexibility in design and in its ability to match colors and existing designs—in this case, matching old terrazzo with new,” Fujikawa said. “Amici did a wonderful job; we are proud of the design, the client was happy and it was on budget. It’s an example of everything going well.”