|Crown Hall - Decline and Rebirth
The decay of a modernist icon, and it's road to restoration, in numbing detail..
It began with a bit of archeology, "trying to get to the bottom of all the stories," says Gunny Harboe, apreservation specialist whose projects have included restoring the Reliance Building to its original brilliance, and putting back Louis Sullivan's original cornice on his Carson Pirie Scott building. Considering how many former Mies students still teach at IIT, the clash of memories must have sometimes been like something out of Rashomon. Harboe's research paid off, however, and not just at Crown Hall. The entire IIT campus has just been placed on the National Register of Historic Places.
The south porch came first. It was completely rebuilt; a new steel structure and new travertine. Research is now being done to find a sealant that will prevent the kind of deterioration the stone suffered in the past. The salt which would melt the water and then refreeze was a real contributing element to the deterioration of the travertine, says Sexton. Travertine because of its open cell system has water coming into it on a daily basis. The salt added to that. When we started taking this building apart, we noticed on the north entry a huge deterioration of the steel right at the sill of the entry, and it was really the salt. The amount of salt that was used there really just ate the steel apart. The sealants now being tested are expected to protect the travertine, but let it breath.
The $3.6 million phase of the restoration that took place over the summer break was the most ambitious so far. Every one of Crown Hall's 340 windows were removed, leaving only the spare, structure, repainted at least three times since 1956, which was then sandblasted down to the original bare steel. Sexton and his workers discovered the individual members still had U.S. Steel or Bethlehem Steel stamped on them. The craftsmanship of raw steel members was beautifully handled, says Sexton. It was a great testament to Mies that he was actually using off-the-shelf material, but he was elevating how it was put together.
Replicating the original paint was another research project. The original, Superior Graphite #30, developed by a bridge company, Detroit Graphite, couldn't be used because it was lead based.
They're also out of business
adds Beltemacchi, No one's making a graphite pigmented paint anymore. There was a Germany company that made it for a while, but they finally decided they weren't going to put really expensive paint on it, because Mies's idea was to use good, sturdy stuff, but frugal, and they found another supplier.
"They were actually very conscientious," says Sexton. "They would spray an entire elevation, and we would reject the entire elevation. They sprayed the entire east elevation and south elevation and we said, rejected. The amazing thing was what they said was, 'yeah, we understand.' There was very little whining. They understood what they were getting into."
Stops! . . . In the Name of Love . . .
The original glass of the upper windows was a quarter-inch thick, and it moved and sometimes broke in the wind. City code now requires glass to be a half-inch thick. "As glass gets thicker it gets greener," says architecture dean Donna Robertson. "The Coke bottle effect, as its called. We switched to what is a low-iron glass. Some people call it the superwhite glass. There are only two manufacturers from whom we could buy a piece of glass of that type in this size. It took ten men and a crane to hoist the glass in the air and then slide it into the steel frame of the building."
"Those who agreed with us," says Robertson, " which were Krueck and Sexton and Gunny Harbor, thought it was better to compromise on the issue of only off-the-shelf stock, because otherwise we would have had to either thicken up the whole stop in order to buy it off the shelf, or . . . use a custom member if the issue is only about right angle relationships, which is another reason not to use the slope because this is a building about the right angle relationship. Because to do that, we'd have to use a custom stop because you'd have to have an L shaped stop that allows there to be that same bite to the glass." The decision to go with a slightly heavier, trapezoidal stop was opposed by the purists as a betrayal of Mies's commitment to right angles.
"We had major issues," adds Sexton, " about how the counter-synching of the screws were done. We had a big challenge with stops coming out and the counter-synching being too deep. It was too deep by about a 32nd of inch. In steel construction, a 32nd of an inch is an unheard of condition. Here, they were all rejected - there's a lot of scrap metal out there because huge amounts were rejected - all remade because of something like that, because there's so little of anything, as soon as it's not right, it's a glaring mistake."
The lower panes of glass, doubled to each large pane above and milky-white to provide a measure of privacy, presented another problem. Mies's originals had been sandblasted to create a white translucent finish. They were all replaced in 1975 with two eighth-inch panes of glass and a plastic film sandwiched in between. "We went to the laminate because of the breakage and the number of people that got hurt from it,"says Beltemacchi, but the result was less translucent than opaque, casting reflections back into the building.
"One of the things that's changed," explains Sexton, "is that there's now federal code that requires all of this glass to either to be laminated or tempered, and at the time in 74 or so you couldn't really temper a piece of sandblasted glass because when you do, you get a very thin layer of tension on the glass, and the sandblasting, because it was all done by hand, would break through that and it would be prone to breakage, so that wasn't a good condition. When Mies did the original building, this glass was not tempered. It was just annealed. Now by law we have to temper it, but because of advances in sandblasting technologies, it's all done by computer mechanism, and they now take off such a thin layer of glass . . . We went and researched this.
Sexton and his colleagues compared more than 100 types of glass, then mounted five full-size finalists in the hall's north facade next to one of Mies's originals. More "What would Mies do?" discussions ensued. "One of the main companies in the U.S.," says Sexton, is a huge company called Viracon, and they have a whole division that's just researching sandblasted glass, and through their research they're realized that they can now sandblast and temper a piece of glass." The glass chosen for the restoration "is now fully compliant with code, and it goes back to what Mies had originally envisioned for the building. You can see the different tones. You can see the sidewalk, the grass and the sky as three distinct colors. You couldn't do that before. "
Free of controversy was the restoration of the continuous strip of operable vents beneath the bottom windows all along the building's perimeter. Harboe says that in their previous condition, they were so corroded, many of the original chains broken, that they were all either always open or always closed." Now, says Robertson, "They're operable. They're exactly as Mies had them. Debate raged about whether to paint the hardware black, and in the end, it was decided to do so. And the only change that was made other than just cleaning it up and taking out the rust was that we put a bug screen on it, and that will make a huge difference in terms of the usability."
Mies's later glass boxes would become sealed environments dependent on mechanical air-conditioning, but Robertson says he was a "proto-green" architect who "understood natural air." Fresh, cool air flowed through the vents at floor level, and hot air flowed out through vents in the ceiling-a simple convection effect that's been rediscovered by contemporary green architects, such as Matthias Schuler, an internationally recognized innovator in green design whose company, Transsolar, along with Atelier Ten, were environmental consultants to the Crown Hall restoration.
While the lack of control and often erratic heating and cooling can be a major irritation to a building's workers, managers tend to love the sealed box and the automated air conditioning because it neither requires human action nor leaves itself open to human action screwing it up. When Crown Hall opened, the lighting and ventilation management system was a man named Ludwig Hilberseimer.
Ludwig Hilberseimer, says Robertson, was brought by Mies from the Bauhaus here to start the architectural program that Mies headed up. Says Beltemacchi of the vents, and of the Venetian blinds that cover the huge upper panes of glass, Hilberseimer used to walk around and adjust them all day long. Hilberseimer and Mies definitely knew about the light control, because when they adjusted the blinds, a lot of it was to get some light up on to the ceiling to get it out onto the tables. We talk about it today, but it was well known in those days. Light control just by adjusting the Venetian blinds was part of the original use of the blinds.
Hilberseimer ran this place with an iron fist. No feet on the furniture. You couldn't play music. You couldn't smoke. It was like schools used to be. People would still wear neckties to class, Hilberseimer, when he died in 1967, that's when the Venetian blind business went to hell. We don't have anyone who does that anymore. Maybe you can't with modern students, but it worked in those days.
Robertson and Sexton are hoping to counter that indifference with a third phase of restoration, estimated to require another $5,600,000. We're going to cut down on the energy consumption of this building, which we can do very dramatically in terms of electricity. We're going to build a building brain that will automate the blinds, so that we modify the blinds to be a modified light shelf. Right now, the concavity of the blade goes down. We're going to flip that, so it goes up. That way sunlight is going to bounce further into the interior, rather than relying so much on the electrical lights. And the lights will be controlled by the building brain as well because it will read what the foot candles are in any point in time. Robertson hopes to also augment the building's original ambient heating tubes in the floor slab with the capacity to carry, not steam, but tepid water to provide cooling in warmer weather. Next: The Legacy of Crown Hall.
Next: The Legacy of Crown Hall.
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