Roof Project Becomes Odyssey

February 13, 2004
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CHICAGO — Now here’s a challenge: Crouch in an 18-inch gap beneath a 500-foot steel and concrete tube through which an El train roars about every 10 minutes — all the while meticulously spraying polyurethane foam to form a 1.5-inch-thick roof.

It’s the kind of challenge that makes Bill Sleeman’s employees exchange rueful glances whenever he announces he has a special project.

Sleeman, 40, is the president and founder of Noble Coatings & Roofing, a company that installs brick-hard, lightweight, spray-on polyurethane foam roofing, a product of BASF.

“Flat roofs are our bread and butter,” Sleeman said. But he said the firm keeps encountering challenges like the one in Chicago — projects that at first seem impossible to him and his staff but that they somehow work out.

The Chicago project actually entailed spending last summer in two distinct phases. The first was spraying on the coating of a 100,000-square-foot roof, part of it in the very tight, under-the-tunnel setting.

Second came the company’s invention of a way to impose a textured wood-grain pattern on the roof — and in the end being directed to impose it instead on the façades of the building in question.

The building is the $42 million McCormick Tribune Campus Center at the Illinois Institute of Technology.

Twenty of the campus’s 50 buildings were designed by the late Ludwig Mies van der Rohe, dean of the institute’s college of architecture from 1938 to 1958. Many more of the structures have a van der Rohe flavor because his students did the design work on them.

The center’s designer is Rem Koolhaas, a celebrated Netherlands architect making his mark with his first U.S. project in a style consistent with van der Rohe’s campus.

The center’s focal point is a van der Rohe interpretive center. The center also houses student organizations and services, dining, entertainment and retail facilities, a bookstore, and multi-purpose meeting rooms.

Sleeman explained that Koolhaas’ commission was to design the center on property lying in the center of the campus directly beneath and either side of a stretch of El track.

The El’s location dictated designing the building with a roof forming a shallow V. Mounted on brackets just inches above the V’s apex is a 530-foot oblate tube — 35 feet high and 60 feet wide — through which the El trains run.

Sleeman said the arrangement dictated a sound-insulating roof, and Chicago’s building codes required a water-retaining roof, because storm runoff is a big problem in the Windy City. The water retention requirement — not to mention snow and ice — torpedoed Koolhaas’ original plans for a wooden roof.

Moreover, it seemed about to torpedo the entire project because the general contractor was stumped for ways to create a synthetic roof that would fit the architect’s requirement that it look like wood.

That’s when Sleeman, who formerly worked in Chicago, pitched the general contractor on a roof from Noble.

“After I told them what we could do, and how much weight and how much money it would save,” Sleeman said, “they just asked, ‘You’re from where?’

“And then they told me, ‘You’re just a little outfit. You won’t be able to work in Chicago. You don’t know the ropes. You’re non-union,’ and so forth.”

Sleeman does know Chicago, however, having worked there before founding Noble Coatings. His firm wound up getting the job as a subcontractor to a former associate, the project’s roofer. Nobody else, he said, could meet the specifications: a seamless 1-1/2-inch thick roof with no more than a 1/4-inch variation in height, and with an imposed wood grain.

“Our work for this project was much more meticulous than what is typically required in an industrial setting,” Sleeman said.

He said most of Noble’s customers want a seamless roof system for its insulation value and “green” features. “You can renew it without tearing it off like most conventional roof systems when they reach the end of their service life,” he said. 

“But on this job they were also looking for a very smooth, aesthetically pleasing surface.

“This project had to hold up to the scrutiny of both engineering firms and the world’s top art and architectural critics. My crews were a little anxious when we first started this project.”

Now, he said, they’re proud of their accomplishment, particularly because the project got a big photo and a write-up in a November edition of People magazine.

The close tolerance roofing, Sleeman said, was difficult but doable, thanks to his firm’s secret weapon — a supervisor named Dave Roest who is a master at spraying polyurethane foam.

Spraying a uniform surface requires intense concentration, Sleeman explained, because binary chemistry mixes in the spray nozzle and begins expanding as it emerges. It continues expanding once it settles on the underlayment, too late to make any corrections.

“In 30 seconds it sets up,” Sleeman added. “And that’s it. You either get it right when you spray it on or it’s a big mess.”

The foam is light — weighing only 50 pounds per hundred square feet — easily supports a man’s weight and is impermeable to water. It is vulnerable, Sleeman said, only to UV light, and that’s why once it’s in place, the firm coats it with a rubbery 36-mill (roughly a thirty-second of an inch) sealer.

Sleeman said that Roest and his small team — one man behind him to support the weight of the hose and two to maneuver a screen that intercepts highly adhesive spray drift so that it won’t get onto cars, other buildings’ windows and the like — spray the material in 6-foot swaths that are about two feet wide and join seamlessly with their predecessors.

He said that when the weather cooperated, they were able to complete about 6,000 square feet in a day.

“The problem working beneath the El tube,” Sleeman said, “was that he had to crouch under there and still achieve a uniform roof surface.”

While that was going on, Noble was perfecting a kind of a polyurethane version of a silk screen held together by netting to create the impression of wood grain which the architect wanted for the roof.

“We want to be roofers, not artists,” Sleeman said, “but we worked with the pattern they provided us and came up with a way to print a wood grain on the roof.”

That’s when it occurred to the architect that — with the possible exception of a few very sharp-eyed El passengers — the wood grain effect would be visible to virtually nobody. Besides, the project was threatening to run over budget.

The architect liked Noble’s ersatz wood grain, however, and asked that Noble Coatings impose the grain on the center’s exterior walls and in its courtyard.

“The guys really rolled their eyes at that,” Sleeman said with a chuckle.

“We’re roofers,” he said. “We even do floors. But vertical work?” Realizing even a weird job is valuable during a recession, however, Noble Coatings did the facade of the campus center.

And since then, word about Noble’s flexibility has spread.

Sleeman said there was a job in Ohio that entailed coating the underside of a false ceiling — of an interstate highway overpass.

And Sleeman may need Roest’s special talents for a job in the Carolinas — a project that would entail sealing the deteriorating interior walls and bottom of a community’s concrete water supply holding basins.

“The guys are saying, ‘Oh, no. Here he goes again.’”

“But if we can do it,” Sleeman said, “it’ll save them from building new basins. It’ll save them millions.”    

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