The Judd Foundation is finishing preparations to open 101 Spring Street to the public, an 11-year effort that culminated in a remarkable restoration by New York-based Architecture Research Office (ARO). This outcome was not at all certain—or even likely—when the artist Donald Judd passed away unexpectedly in 1994. The Chinati Foundation, the collection of permanent art installations that Judd created in 1971 on a disused army base in Marfa, Texas, was run as an independent nonprofit organization by the artist’s companion. He also had two grown children from his first marriage. In his decades in Marfa, Judd practiced permanent art installation by buying and altering houses and buildings in town and across the desert. Space was his artistic medium. The artist’s estate as such contained art, real estate,  debt, and little cash. Judd first developed his concept of space at 101 Spring Street, his home and studio in lower Manhattan. Judd purchased the five-story corner loft building in 1968 to make his art, raise his young family, and house his cactus collection. The fading manufacturing neighborhood was then called the Cast-Iron District; it soon became known as SoHo. Judd’s home and aesthetic were influential archetypes of the artist’s loft. ARO set out to preserve Judd’s original interpretation of historically commercial architecture.

The artist described his renovations as “an act of cleaning.” But Judd also made subtle but significant alterations to the spaces of his 1870 building. He opened up each floor toward the uninterrupted windows on the western and southern façades. He carefully articulated the ceiling and floor planes. Then he installed his own art and that of his friends, including Larry Bell, John Chamberlain, Claes Oldenburg, and David Novros. Judd designed and collected furniture for each of five floors that best served that floor’s single function, in ascending order: meeting, eating, working, socializing, sleeping. 

This process proved foundational for Judd’s own Minimalist sculpture and his revolutionary ideas for how artwork should be shown and experienced. It concerned the definition of pure form through the removal of the extraneous, and the experience of spatial clarity through the relation of every part to the whole. For example, Judd removed every light fixture, pipe, and sprinkler to transform the sloped ceiling on the fifth floor bedroom into a single, unobstructed plane. This ceiling was a precedent, Judd wrote, for the interior variations in his greatest work at Chinati, 100 untitled works in mill aluminum (1982-86), housed in two former artillery sheds. More broadly, though, 101 Spring Street was where Judd first realized the idea that led to Chinati: the “permanent installation” of artwork in a space created or refined specifically for it.

 The nature of his changes to these spaces made the restoration of 101 Spring Street and its conversion for public use anything but a foregone conclusion. His changes were inalterably exacting. Many were illegal under current fire and accessibility codes. (Judd had never let the fire inspector inside, said his daughter Rainer, who is named after the avant-garde dancer Yvonne Rainer.) Yet to maintain the 8,500-square-foot building as a single private residence was untenable. Rainer and her brother Flavin (who is named after minimalist artist Dan Flavin) lived and worked mostly in Los Angeles. SoHo had become the luxury lifestyle destination that it is today; Rem Koolhaas’s Prada Epicenter opened up the block in 2001. To sell or rent out the Gesamtkunstwerk would be to destroy it.

The Judd children received exhaustive amounts of advice. In 2002, they decided to keep 101 Spring Street somehow, under the auspices of The Judd Foundation. The Foundation’s mission is to preserve in perpetuity the art-installed spaces that their father created outside Chinati: fifteen buildings in Marfa and the one in New York. In 2005 they made the controversial decision to auction twenty-some million dollars of Judd sculpture in order to finance restoration of the foundation buildings, starting with New York. In 2006 they engaged ARO to develop a plan. The original budget was around $8 million.

The tenor of the project changed completely when Arup Fire devised a smoke evacuation system with fire-activated robotic baffling to instantly enclose the illegally open fourth floor staircase. When they realized the most seemingly impossible-to-salvage of their father’s interventions could be preserved, Rainer and her brother committed themselves: They decided their every decision had to preserve the balance and the essential experience of Judd’s spaces.

“I just remember the grueling discussions we had about keeping the open floor plan (on four),” Rainer Judd says, “and when we found we could keep the open floor plan, what about everything?” ARO’s principle for modifications was “virtual invisibility” says project architect Adam Yarinsky, FAIA. It’s an approach that the project’s namesake would have insisted on. Donald Judd once described architecture as intention and building as expedience. He tirelessly pursued the former while avoiding the latter.

“In order to preserve the inside, every inch of noninstalled space was used,” Yarinsky says. Rather than let modernizing renovations compromise Judd’s spaces, or resort to what Rainer Judd calls “stupid hiding,” it was better to take time to engineer a solution that fit the building’s limitations. “Time is not a factor,” Flavin Judd explains. “Because everything we do is permanent, it doesn’t matter how long things take.”

Such planning and problem-solving took eight years. The budget grew to $28 million. The foundation raised several million additional dollars through complex financial maneuverings to monetize the federal tax credits associated with historic preservation, which are typically not exploitable by a non-profit.

In 2010, Yarinsky says, ARO began the process of “essentially putting an entirely new building inside the old building,” and taking apart the old one. Construction management firm Sciame encased the building in climate-controlled scaffolding for more than two years. Walter B. Melvin Architects removed the 1,300 pieces of the cast-iron façade for stripping and zinc priming; around 400 pieces were recast. The roof was removed, reinforced, and rebuilt. Air handling units, smoke evacuation fans, and the emergency generator were installed on it, Yarinsky says, “like little backpacks on an astronaut.” The fifth floor ceiling was reconstructed at its original, inspirational cant.

All 60 casement windows were dismantled and reglazed with restoration glass. Judd’s worn battleship gray paint on the casements was preserved as-is, Yarinsky says, as a “fundamental piece of the experience. I think a lot of the crudeness of the building, and a lot of the economy and straightforwardness of how he worked, is what makes the space feel special.”

Considerable effort was made to work with what’s there. This contributes significantly to the aura of economy that the Judds spent so much to preserve. The worn, wooden stairs and the ancient, open-roof freight elevator appear to be completely unaltered. The elevator has received a new mechanical system and serves as an integral part of the building’s Americans with Disabilities Act accessibility. As the only light fixture on the fifth floor, Dan Flavin’s 65-foot-long light installation was wired to function in the event of an emergency as egress lighting. The formulation of the rough base coat plaster Judd used on his studio wall is no longer produced—so artisanal plaster was commissioned to replicate the effect.

Yet some things are not identical or invisible. Climate-control systems require vents, and these are quite apparent in the walls of the ground floor. A loft space above the second floor kitchen that used to contain a futon now holds a climate-control apparatus the size of a credenza. ARO enclosed this, mechanical closets, and other visible elements throughout the building in quiet, yet distinctive, poplar tongue-and-groove paneling. The current ubiquity of Judd’s own historical vocabulary complicated this effort. “Judd’s aesthetic has become the vernacular of contemporary art galleries,” Yarinsky says. “The key was finding the right expression for new elements we were adding that would feel of this place, but not mimic it.”

But the building also includes spaces that are extraordinary and new. ARO created offices for the Judd Foundation, along with conference rooms and ADA-compliant restrooms, in the basement and sub-basement. The spaces also contain mechanicals behind walls of ARO poplar cabinets. A pivoting door reminiscent of Judd’s design for Chinati separates the public and private areas. Vault lights on the hollow sidewalk provide illumination to the basement, while original floorlights provide illumination to the sub-basement.

The spaces on the above-grade floors of 101 Spring Street are essentially Donald Judd’s, expertly conserved, stabilized, and made available to the public. They are Judd’s highly influential adaptations of 19th-century architecture and his particular installation of artworks. They are time capsules of a sort, and of several eras: from the 1970s, when the artist began his alterations, to 1983, when it was largely settled, and to 1994, when he suddenly passed away. Judd’s installations at 101 Spring Street are now among the most significant architectural spaces in SoHo, and among the most important artist spaces in the country.

The Judd children, now co-presidents of the foundation, sit at desks in the space that was once their basement-level teenage lair. “All that wood is original to the way Don built our bedrooms,” Rainer Judd says, as she points to a basement wall. The rest of the below-grade space “was where Adam and Flavin could make something new.”