Who's to blame when a building designed by a famous architect has exterior walls that are rotting? How all involved in an architectural project must learn to speak the same language
Years ago, in Washington, D.C., I had dinner with Peter Blake. Peter was at that time teaching architecture at Catholic University. But he was best known as a journalist—a former editor of Architectural Forum and the founding editor of Architecture Plus, two of the best architecture magazines of the 20th century.
Peter also wrote books, and books were the subject of our dinner. He spoke of a famous series of articles in The New Yorker by Berton Roueche, called "Annals of Medicine." Each was a medical detective story. A patient would come down with some bizarre symptom and doctors would work to trace the cause the way detectives trace the perpetrator of a crime. Why not, mused Peter, a book like that about architecture?
Think of the famous Hancock Tower case in Boston as a medical problem. Here was a building with a mysterious skin disease. Its 10,000 mirror-glass cladding panels were cracking and failing. Nobody knew the cause. Maybe the foundations were settling? Maybe the building's rhomboid shape created pockets of high winds? Maybe the slender tower was waving back and forth too much?
It was years before the cause was finally isolated, as a defective design by glass supplier Libby Owens Ford. (The Hancock's "doctors"—the forensic engineers—also determined that the building was in danger of falling over, but that was an unrelated medical problem.)
Peter suggested that the two of us should collaborate on an Annals of Architecture, starting with the Hancock. Alas, we never got around to doing it. But I still think it was a good idea.
So here's a late-inning shot at one such annal. Once again, we're talking about a case of architectural skin disease. For a long time, nobody could diagnose the problem. By the time the experts did, they decided that the best solution would be to kill the patient—the building—and start over. That's the "cure" that's now about to be implemented.
The building is Werner Otto Hall at Harvard. It is a three-story addition at the rear of the university's famous Fogg Art Museum. Otto houses Harvard's Busch Reisinger Museum, which houses a major collection of Germanic art, mostly of the 20th century. Indoors, it's a delightful set of galleries. Outside, it's a rotting mess.
Otto opened in 1991. Today, 17 years later, its exterior walls have deteriorated so badly that Harvard says the only way to repair them would be to take them off entirely and start over.
Yet this disaster was created by the best and the brightest.
The client was Harvard, or more specifically, its Faculty of Arts and Sciences. The architect was the firm Gwathmey Siegel, known for its superb 1992 addition to another museum, the Guggenheim in New York, among other buildings. The general contractor was Walsh Brothers, a Boston firm now in its fourth generation that has long been regarded as one of the region's best.
Otto was much praised when it opened. It was a clean example of Modernism, bold but not so bold as to upstage the more celebrated Carpenter Center next door, by Le Corbusier. Inside, it offered a series of small galleries that flowed into one another in unexpected ways.
Thus, it's hard to believe that today the entire building—not just the wall, the whole thing—is slated to be completely demolished and removed. New construction will engulf Otto's former site. The new work will be part of a major addition to the museum, being designed by Pritzker Prize–winning Italian architect Renzo Piano, due to open in 2013.
When you talk to Harvard's facilities managers, they try to draw your attention away from Otto's sick wall by claiming that Otto just didn't fit in with plans for a new, larger museum, so it had to go anyway. But Harvard also admits, when pressed, that the exterior wall was probably incurable.
So what happened? What's the diagnosis? To put it simply, the guys who worried about the museum's art were not the guys who worried about the weather. It was a classic failure of communication. We'll call them the art guys and the weather guys.
The art guys, applying a conventional standard, decided that Otto's interior should be kept at a temperature of 70 degrees, with 50 percent humidity. Those numbers would be best, they believed, for the health of the artworks.
Not only that, but the museum curators and conservators asked that the interior be pressurized, like the fuselage of an airplane. They didn't want cold, dry Cambridge, winter air slipping in and damaging the precious art. If there were going to be any air leaks through the exterior wall, the curators wanted to be sure the air would leak out of the building, not into it. The museum owned world-class stuff, including what may be my favorite Harvard treasure, a fantastic self-portrait by Max Beckmann standing in a tuxedo and holding a cigar, an image of hollow and doomed sophistication.
Making new demands
It's important to understand that this kind of sophisticated climate control was still fairly new at the time Otto was designed. Art conservators were making demands that neither the world of architects nor the world of engineers and contractors had quite caught up with.
Okay, that's the art guys' story. The weather guys—the architect, his engineering consultants, and the builder—created pretty much the kind of wall they'd always built. Its primary purpose was not to nurture the art but to keep out the weather. They built a cavity wall, a sandwich of materials including a vapor barrier. They finished Otto's exterior in porcelain enamel panels, thin limestone panels, and glass windows. They finished the interior in ordinary drywall.
Several things went wrong:
The pressurized interior air naturally tended to leak out through the wall. You can think of the building as a big machine for the purpose of pumping moist indoor air into the cavity. When it got there in winter months, of course it condensed. The condensation sometimes froze. The wall began to rust and rot. There were times when it was soaked through.
Most of the people I talked to blame the vapor barrier. They say it was mislocated, or that it failed. Architect Charles Gwathmey is one. He believes his wall design was not to blame and suggests other possibilities. "Somebody must have cut holes in the vapor barrier after it was installed," Gwathmey says. "Maybe a subcontractor installing plumbing or telephone connections."
Vapor barriers do, in fact, get punctured. Andy Sebor is a Connecticut mechanical engineer who is a recognized expert in this field. He says failures of this kind are common in art museums of Otto's vintage. He notes that at the Davis Museum at Wellesley, a building by another Pritzker-winning architect, Rafael Moneo, the curators themselves caused problems. They ruptured the vapor barrier by drilling holes to hang artworks.
"You have to keep the vapor barrier away from the owner's drill bit," says Sebor wryly.
Sebor says that both construction methods and curatorial demands were changing in the years leading up to the Otto. "We engineers let architects and curators go off on their own," he says. "There was a lot of wishful thinking." Architects today, says Sebor, are more sophisticated, especially in cold climates.
The role of a barrier
But all the talk about vapor barriers misses some of the point. The purpose of a vapor barrier, pace Gwathmey, is not to prevent moist air from penetrating the wall. It is to prevent water molecules in that air—not the air itself—from diffusing through the barrier. It doesn't matter if there are a few holes. The barrier will still retard molecular diffusion.
The bigger problem comes when the moist air itself penetrates the cavity. Besides the vapor barrier, which usually won't prevent that, there must be an air barrier, which must have no leaks and must be strong enough not to be ruptured. The two barriers can be combined into one, or they can be separate.
I realize that many readers are going to know more than I do about this problem, so I'll merely recommend the best source I found. This is an article, "Condensation in the Building Envelope," by Vincent Cammalleri of the engineering firm Simpson Gumpertz & Heger (SGH). It's on the AIA Web site: http://www.aia.org/SiteObjects/files/bsci_cammalleri.pdf. SGH won't name its clients, but clearly the firm is seldom lacking in museums that need help.
There are a couple of other lessons to be learned from Otto. One is that long-term institutions like Harvard should build durably, as they did in the past. They're short-sighted when they indulge in the cost-cutting that's common in the commercial world. At Otto, the exterior metal panels were connected to the framing structure by galvanized ties, which quickly rusted from the moisture. They should have been stainless steel.
Another lesson is always to ask where standards come from. Indoor humidity of 50 per cent is an arbitrary number, one that may not be right for cold climates like that of Cambridge, with its frequent freeze-thaw cycles.
Finally, of course, the art guys and the weather guys should be sure they're on the same page, that neither is doing something that will sabotage the work of the other.
Otto's health was never restored. Nothing worked quite right. The interior never made it up to the desired 50 percent humidity because of the leakage. Even the windows didn't work. They lacked thermal breaks, meaning they, too, could become sources of condensation. (That problem was Band-Aided with heated electrical tape.)
Harvard sued the architect and the contractor in 1996. As usual in such legal matters, neither side will talk for the record. But word on the street is that the parties split the cost of repairs—repairs that proved, in the end, not to make any difference.