After a year-long restoration, Frank Lloyd Wright's famous research tower at S.C. Johnson's headquarters in Racine, Wisconsin, is set to reopen in May. It's a triumph of modernism. The facade is made up of thousands of glass tubes, hovering in between tiers of red brick, all of it supported by cantilevered steel beams.
But pay attention to those materials -- steel, glass and brick. How would you begin to restore a piece of glass, or an I-beam? It's a conundrum facing preservationists across the country: What does it mean to restore a building made out of modern materials?
"Fundamentally, I think we need to think of preservation and restoration differently when we look at modern buildings," says Leo Marmol, a principal at Marmol Radziner Architects, which has restored many modernist structures. "Modern buildings work to minimize the amount of material to begin with -- less and less gives you more. But those materials tended to be new, synthetic materials, many of which did not perform well over time." To preserve modern buildings, he says, "we have to accept that we will lose a great deal of historic fabric in the process of repairing or replacing a building's assembly."
So restoring a modern building often means replacing materials, not conserving them. That approach contrasts starkly with pre-modernist restorations.
"If the building's made of stone, you can neatly cut the piece of bad stone and put in a new piece," says Gunny Harboe of Harboe Architects, which is currently restoring Frank Lloyd Wright's Robie House in Chicago. "It's much harder to do that with, say, concrete."
What distinguishes the restoration of a modern building from a replication depends on what makes the building distinctive, says Susan Macdonald, the head of field operations at the Getty Conservation Institute.
"Is the glass really important, or is it the structural conception of the building that makes it significant?" she says. "The first thing you do in conservation is look at the building, and that gives you clues for what you can trade off."
Is the S.C. Johnson tower a true restoration, then? By such standards, the answer seems to be yes. The tower's signature bricks have been restored rather than replaced. More than a thousand of the tubes have been cleaned, and several thousand more have been replaced with the same glass as the originals. (S.C. Johnson declined to name its architects.)
Classifying a modernist restoration is still an inexact science. "I wish it were easy to say, 'You do X and you've fallen over the precipice of inauthenticity,' " says Marmol. "It's not quite that easy. The preservation of modern buildings is a new enterprise."
Not for long. "We're coming to the point where virtually all of them will be threatened," he says. "If they're not already, they will be soon."