Crown Jewel

Approaching its second half-century, Crown Hall—Mies van der Rohe’s eloquent 1956 expression of an architecture of beinahe nichts (almost nothing)—was in need of a major face-lift. Decades of neglect had left the Illinois Institute of Technology (IIT) building’s south porch crumbling, much of the glass cracked and scratched, the chipped paint fading, and the steel frame rusted by moisture from the Boston ivy crawling freely up its sides and corroded by ice-melting salt. Getting back to “almost nothing” was going to be a lot of work.

In 1995 a new IIT administration committed to updating its Mies-designed campus—including the Crown Hall centerpiece—adding bold new buildings by Helmut Jahn and Rem Koolhaas in 2003. This year a team who had studied with and worked for the master—including School of Architecture dean Donna Robertson, preservation specialist Gunny Harboe, project architects Mark Sexton and Ron Krueck, and a Greek Chorus of professors and alumni—considered the evolution of materials and technologies against today’s more demanding building code. Debating what Mies would do, they created the $3.6 million plan that has returned the landmark to his original vision. Completed during the 14-week summer break, the results are spectacular, like stepping into a time machine and encountering the building when it was newly minted—startling, serene, and glorious. Here are some highlights of the restoration.

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Travertine
The south porch—whose steel structure had deteriorated to the point of being unsafe—was completely rebuilt, its marble surface replaced. “It’s not the greatest paving material,” Harboe says. “If Mies could have afforded it, he would have used granite. But the reality is that he used travertine.” A new sealant, still to be selected, will be applied to the travertine to make it more durable.

Steel Frame
The structure was sandblast-ed down to the original bare metal and sprayed with 800 gallons of a three-part Tnem-ec system used for painting bridges. What was for more than four decades a dull gray finish is now a rich glossy black that reflects Mies’s original intentions.

Upper panes
All 340 windows were removed and replaced with 30 tons of new low-emission glass to reduce heat loss. Code required taking the massive 111/2-by-91/2-foot upper panes from 3/8- to 1/2-inch thick. Low-iron superwhite glass avoids the greenish coke-bottle effect common with added thickness.

Window Stops
At 5/8-inch thick, the original L-shaped Mies-designed stops were no longer adequate to secure the 700-pound upper panes in place. The trapezoid-shape replacements, which are 1/8-inch thicker with a tapered bevel, evoked controversy from purists, who opposed the diagonal imposition into Mies’s rigidly right-angle aesthetic.

Lower Panes
Prone to breakage, Mies’s milky-white sandblasted glass was replaced with a more opaque tempered laminate in the 1970s. For the restoration more than 100 alternatives were considered before an innovative glass developed by Viracon was selected. Both sandblasted and tempered, it returns to the translucency of Mies’s originals.

Vents
Crown Hall was never a sealed box. Fresh air was brought in through operable floor-level vents along the building’s perimeter, and warm stale air was drawn out through the ceiling. Over time rust had locked individual vents; now all 112 are restored and functioning, with a bug screen added to each.

Blinds
The old blinds, yellowed with age and cigarette smoke, were replaced with ones that are strikingly white against the painted steel. The next phase of restoration proposes automating the blinds and reversing the blades’ concavity to bounce sunlight deeper into the interior, part of a plan to decrease energy consumption that also includes running cool water through the floor.

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