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Inside Louis Kahn

How to update buildings designed with nothing to hide? Tales from the renovation architects who know Louis Kahn best

Yale Center for British Art, fourth floor, Turner Bay following reinstallation
Yale Center for British Art, fourth floor, Turner Bay following reinstallation
Richard Caspole

I do not like ducts, I do not like pipes. I hate them really thoroughly, but because I hate them so thoroughly, I feel that they have to be given their place. If I just hated them and took no care, I think that they would invade the building and completely destroy it.

Louis I. Kahn in World Architecture, 1964

Reyner Banham quotes Kahn in The Architecture of the Well-Tempered Environment (1969), a book that marks a critic’s first attempt to grapple with the technological innards of the building, his hand forced by an architect’s insistence on giving them form. Banham points to Kahn’s Richards Memorial Laboratories (1961), at the University of Pennsylvania, as the project that has caused him to retrace the steps of modernism, looking for poetry in radiators, overhangs, and curtain walls. "Effectively," he writes, "what Kahn has done is to provide the laboratories with monumental cupboards in which the services he hates can be forgotten because [they are] outside the plan of ‘the building.’"

What Kahn could not put in a cupboard—faced in brick and grouped to form a protective carapace around the windowed labs that were the primary purpose of the building—he threaded through the concrete trusses of the ceilings, correctly assuming that most would be so distracted by the structure, they wouldn’t mind the spaghetti.

Banham continues, "This solution was taken to be universal and general, and imitation was so instant that Colin St John Wilson had to enquire (Perspecta VII) "Will ‘servant spaces’ be the next form of decoration?" And lo, they were, with the Centre Pompidou’s facade of pipes and ducts as chief example.

Banham’s flip, from Kahn as a master craftsman of monumental, timeless space, to Kahn as a master tinkerer, threading heat and air and light around that empty beauty, seems even more perceptive today. As the innards of many of Kahn’s buildings reach the end of their useful lives, their renovation architects are opening those cupboards and crawling around those ceilings, trying to figure out how to fit the 21st century in with as much care for and as little disruption to an architecture they all revere. There’s nothing dated about naturally-lit rooms, built of sturdy elemental materials, that are still serving (with some tweaks) their original objectives. They need to be cleaned (without removing the patina), heated (so that water doesn’t condense on the inside), brightened (though LEDs are still divisive).

Kahn prior to renovation
Kahn building prior to renovation; photo © Yale University Art Gallery
© Yale University Art Gallery

On the reopening of Kahn’s final building, the Yale Center for British Art (1977), after a multi-year conservation project, I spoke to the architects who now know Kahn’s work better than anyone: the renovators. These architects worked on the YCBA, the Yale University Art Gallery (1953) across the street, and the Richards labs. (Kahn’s Salk Institute for Biological Studies, in La Jolla, is also part of the Getty’s Conserving Modern Architecture Initiative.) Did their impressions change? Did the mystique die? Did the bricks speak?

Rather than asking What Would Louis Kahn Do?, the restorers instead found themselves figuring out what Kahn did do (you can pack a lot into a cupboard), and trying to do more of it. ("I hate the séance approach to preservation," says David Hollenberg, University Architect at the University of Pennsylvania.) Not adding in the manner of Kahn, but fitting themselves and their new pipes and ducts within his systems.

"Buildings have a lifespan after which they need to be renewed, and modern buildings are more delicate because they tended to feature more innovative systems." --George Knight

"If you were to walk into the [Yale Center for British Art] building five years ago, you would have seen materials coming to the end of their lifespan, but not sensed how desperate the situation was," says architect George Knight, who led the project. "Buildings have a lifespan after which they need to be renewed, and modern buildings are more delicate because they tended to feature more innovative systems."

Mechanical, air, and electrical needed to be updated; the building had no sprinkler system and problematic wifi, plus a lighting control system limping along because a gentleman in Florida happened to have a garage full of parts for the 1977 tracks and cans. The YCBA also had far more staff than it did in the 1970s, as well as more requests for teaching and research space.

Knight, guided by a book-length conservation plan authored by Peter Inskip and Stephen Gee, tried to do as much expansion as he could in the back-of-house spaces, where concrete gives way to block, and anodized aluminum to the building’s signature pewter-finished stainless steel. At the end of the Long Gallery, a new wood-lined seminar room does look as if Kahn could have designed it, given its carefully detailed white oak paneling, suggestive of another continent and another century. New wiring was pulled through the original conduits, because there’s little extra space in a building that’s concrete-on-concrete.

Long Gallery, May 2011, Yale Center for British Art
Long Gallery, May 2011, Yale Center for British Art
Richard Caspole

Where technology like sprinklers or security cameras couldn’t be inserted, "the challenge was to integrate them with the same serene order and prevision as he inserted the other systems," Knight says. "His design is so strongly characterized by a recognition that you don’t force mechanical systems in with a crowbar. He began with those systems and let them be the defining qualities of the architecture."

Security cameras, which had begun to have a "barnacle quality" in the corners of the massive V-beams, were reduced to singular objects, all of the same type. Adding piping for sprinklers was deemed too distracting in the galleries, so those were installed only in the building’s offices and two great courts, where they are visible as a line across the grid (a clean, straight line).

The fire shutters in the apertures around the Entrance Court were replaced; they had always been finicky, and in the past, small plaques on the interior windowsills warned visitors not to lean out lest one of the shutters fall. The "pogo panels," movable partitions that allow the curators to rearrange the galleries across the grid, were also redesigned to be closer to Kahn’s original unexecuted concept, with a thin wood strip across the bottom and Belgian linen to match the actual walls.

Yale Center for British Art, Entrance Court following reinstallation
Yale Center for British Art, Entrance Court following reinstallation
Richard Caspole

Mention to an architect that renovations have been underway at YCBA and she blanches, but a visit last week was supremely reassuring. The Center, before or after renovation, is a sumptuous experience. From the quadruple-height entrance court, where Barbara Hepworth hobnobs with a cast of Samson Slaying the Philistine and unfiltered daylight falls upon Kahn’s signature quarter-sawn white oak panels, to the Long Gallery, re-installed salon-style, to the Library Court, where the elephantine concrete cylinder holding the stairs faces off with George Stubbs’s "Lion Attacking a Horse," it is simultaneously grand and modern in a way today’s architects mostly find impossible to pull off.

The materials are simple, but varied, with exquisite details where they meet: white oak in its concrete grid, travertine floors that become travertine treads on the concrete staircase, Belgian linen walls the color of concrete upon which the many many gilded frames seem to float. Even the chairs square the circle between past and retro-present: originally chosen by Benjamin Baldwin, pairs of Don Chadwick’s low slipper chairs, upholstered in a sober brown, sit in the galleries like mushrooms. The originals were still in the building, but somewhat decayed. Luckily Herman Miller recently produced a reissue, somewhat firmer and higher and therefore easier to rise from gracefully.

Alexandra Lange

The fourth floor is particularly lovely, as filtered daylight falls on the paintings through Kahn’s elaborate skylights, held by a cruciform steel structure set atop the thick V-shape concrete beams that define the ceiling’s coffers. The skylights were developed first by Kahn, and then by Pellecchia & Meyers, the former employees who took over the project upon his death in 1974, with lighting designer Richard Kelly. They layer plastic diffuser panels below plastic bubble skylights below metal louvers. From the Art Gallery across the street you can see the skylight popping up across the roof like, as Kahn put it, "angry crabs."

Because the galleries are truly daylit, you are acutely aware of the movement of clouds and the changeability of weather, without ever looking out. And when you want to look out, you can, without going on a search. So many architects today talk about windows as an orientation device: Kahn did it first, and generously. The views across Chapel Street become a palimpsest of real and imaginary Britishness, as you look at a neo-Gothic building completed in the 1920s next to a painting that’s actually 200 years old.

The journey Knight went through in conserving the building was not unlike that of Anthony Pellecchia and Marshall Meyers in 1974. "The task given to us by Yale was to finish the building as if Kahn were still alive," says Pellecchia today. "We knew enough about various systems and attitudes he would have, and some he never got to apply. For example, he was really interested in Shaker furniture. All their furniture against the wall hung on cleats, which was something we were able to introduce to the building. All of the hardware, the outlets and all of the switches and things were totally organized so they were on wood stiles next to the doors, and never on the wall surface where artwork would be hung."

Yale Center for British Art, fourth floor, Long Gallery following reinstallation
Yale Center for British Art, fourth floor, Long Gallery following reinstallation
Richard Caspole

Pellecchia & Meyers were hired by Yale because Kahn’s office was bankrupt. "I wanted to strike out on my own, and have my own firm," he says. "To then be brought back to finish a Kahn building, knowing what we had to do as if we were back in the office…." After a meeting with Kelly in New York, Pellecchia found himself turning to Meyers (who died in 2001), and saying ‘We have to tell Lou everything we just talked about.’"

The systems at the YCBA may have reached the end of their lives, but they hadn’t failed, unlike the glass curtain wall at the end of the Yale University Art Gallery, which, by the time Ennead (formerly Polshek Partnership) initiated a renovation in 2004, was cloudy and cracked, with rusted mullions and a weeping interior wall.

"This was the beginning of architecture where there weren’t a lot of places to hide things," says Ennead management partner Duncan Hazard who, with design partner Richard Olcott, oversaw the renovation. "They tried to do things minimally and also beautifully, and it was tough." The Art Gallery, like Richards, came at the beginning of Kahn’s built career, and "this building was home cooking for him. He was figuring out a lot of stuff, and the more you worked on it the more you could see him figuring it out."

Yale University Art Gallery, Louis Kahn Building, view of west window-wall
Yale University Art Gallery renovation was undertaken by Ennead Architects (formerly Polshek Partnership), led by management partner Duncan Hazard with design partners Richard Olcott and James Polshek. Here, a view of the west window-wall post-renovation on the Louis Kahn building.
Elizabeth Felicella

While working on the gallery, Hazard kept a vintage photo of the building at night, illuminated from within, pinned up above his desk. He loved "the celebration of the transparency of the wall and the ability to see the ceiling. That ceiling is so beautiful, and what it does spatially is so beautiful." To make that image reality again, they had to replace the entire curtain wall—under the watchful eyes of the architects in Paul Rudolph’s Art & Architecture Building across York Street—and make sure Kahn’s cast-concrete tetrahedral ceiling stayed pure.

Like Knight, Hazard and Olcott found there was very little wiggle room in Kahn’s universal ceiling. Ducts and lighting were trapped in a sandwich between the concrete tetrahedrons and concrete floors above, new lighting had to be threaded in three-foot-lengths through the triangular openings (they doubled the number of downlights), and new sprinkler pipes and wiring threaded through the existing ducts.

The views across Chapel Street become a palimpsest of real and imaginary Britishness, as you look at a neo-Gothic building completed in the 1920s next to a painting that’s actually 200 years old.

There were issues with Kahn’s curtain wall right from the very beginning, because the glass units didn’t accommodate seasonal expansion and contraction. Too much pressure caused them to crack. "When we took the wall out we found the edges of the slab had been bent up because the pressure was so great," Hazard says.

On the inside, the single bar radiators were too weak to offset the chill coming off the glass, causing interior condensation. "You would go in on a January day and put your hand on that wall and it would be soaking wet," says Olcott. "It was so bad that right after the building opened Kahn installed drip pans because water would run down the mullions and collect in these pans."

To fix the problems, the entire wall was replaced with new insulated glass, detailed with thermal breaks and made of aluminum detailed to mimic the original stainless steel. The interior mullion was doubled, and reinforced with steel, to meet current wind load requirements. The radiators at its base were doubled up, and scrims, which were part of Kahn’s original design, were repurposed to create a pocket of warm air against the glass. "Usually you have more tools than that," Olcott says dryly.

But while the glass wall was a ruin, the building’s front brick wall "looked like it had been built the day before." Kahn had inserted the building’s hot water pipes between the exterior brick wall and the interior exposed block wall. Heat from the pipes caused constant circulation of warm air in this cavity, keeping the temperature steady. When the architect went to restore the 1920s building abutting the gallery, they copied this technique.

Possibly the most "home-cooking" detail was the looped metal mesh used as the railing in the staircase, also housed in a concrete cylindrical tower, but triangular in plan rather than square as at the YCBA. It had pillowed over the years and was no longer taut, so the architects wanted to replace it. But they couldn’t figure out what it was until, one day, the Ennead librarian glimpsed a similar material used as a backdrop in a catalog product shot. It turned out to be part of a conveyor belt system used for frozen foods, miraculously still in production. They ordered it, this time in a heavier gauge.

"The money came up very suddenly, and Kahn was hired. He had never done a science building before, and he didn’t have a whole lot of participation," says Hollenberg of Richards Memorial Laboratories, which reopened earlier this year after the renovation of two of Kahn’s four towers. "He envisioned science being done on a big wide open floor very much like his own office, but that’s not the way scientists are." Kahn designed the building as wet labs, but it never worked well for scientists, who stuck paper to the windows and ran extension cords over the powerful concrete ceiling grid, cluttering the elevator halls with refrigerators.

In 2014, the university decided to renovate the building for use as offices and computer rooms ("dry labs") keeping scientists in the building but changing its program. Just as Kahn learned about lighting and curtain walls between the time he designed the Yale University Art Gallery and its Center for British Art, so he learned about private offices and larger mechanical rooms in the decade-plus between Richards and the Salk Institute.

The Salk Institute
The Salk Institute
WSquared Photography

As at the Yale buildings, keeping the ceiling clean was a priority. "They became a sacred plane in the office floors, nothing could protrude below those vierendeel trusses," Hollenberg says. (Named after Belgian engineer Arthur Vierendeel, such trusses are able to remain stable without diagonal bracing, allowing Kahn to create an open floorplan under a square grid.) He had more room between the trusses and the slabs of the floor above, but because new chilled beams and lighting systems would still be visible, they had to be chosen and laid out with care. "We had little clues from old night shots which indicated how the lighting was laid out."

While there are now private offices around the perimeter of the spaces, they are separated by glass partitions, and one corner of each floor was left open to convey the original idea of the open plan. Oak, Kahn’s preferred wood, was specified and steel framing was painted gray, close in color to the concrete. Hollenberg and the restoration team also took care to make all the new partitions floor-to-ceiling, and of a single material, in the proper modernist manner.

The windows were replaced and the concrete was cleaned, so "in the building again the dominant color is the concrete. It might share dominance with the green of nature outside the building, because on the south side you feel like you are in a treehouse." Because the scientists are now working on paper and screen, the natural light, the lack of outlets, the limited flexibility are no longer a problem. Those uses are sequestered in new buildings designed after extensive consultation with faculty about their needs. Kahn’s architecture, less pressed, can breathe.

Having retraced Kahn’s steps, and in some cases, retraced Kahn’s drawings, all of the architects I spoke to still had undiminished admiration for the buildings and their creator. Their takeaway seemed to be respect for the very struggle Kahn identified within himself. Even if he wanted to create beautiful ruins, he couldn’t: His buildings had to work for the mid-twentieth century, and for users finicky in a variety of different ways.

The discipline of making space for the servant as well as the served pushed Kahn to simplify both systems. If he could not anticipate the power-hungry needs of 21st century science and art, so be it. I find myself fascinated by the dual vision I have now of these buildings, at once oases of peace removed from the usual messy world, and places in which the mess has been lined up, like a Shaker room, so that it too is an artwork.