Another museum expansion. The mere suggestion is unsettling. An expansion often destroys the gestalt of the original architecture, and the extra space—which usually includes a café, a shop, and a lecture hall—never seems to stop the museum from hankering to expand again, usually because of increased attendance. A house museum, such as New York’s Frick Collection, particularly faces this dilemma, since the domestic scale means that popularity brings with it a sense of claustrophobia as visitors meander around the art, furniture, and artifacts.

Nevertheless, the Frick went ahead and did it: it has undertaken the second-largest expansion since the house, designed by Carrère & Hastings in 1914, was turned into a museum by John Russell Pope in 1935. Selldorf Architects, working with executive architects Beyer Blinder Belle (BBB), has added 27,000 square feet of new construction and repurposed 60,000 square feet, at a total cost of $330 million. Fortunately, Selldorf and BBB approached the task with discretion in their immaculate restoration and renovation of existing architecture, coupled with the bravura of their precisely constructed new additions, all of which have elicited effusive responses since the Frick reopened last month.

In 1912, Henry Clay Frick hired Thomas Hastings of Carrère & Hastings to design a house for him and his family, as well as to display his impressive collection of old masters, such as Corot, El Greco, Gainsborough, Velázquez, and Vermeer. The limestone-clad masonry-block and steel structure necessitated a sizable plot, where Richard Morris Hunt’s Néo-Grec Lenox Library had previously stood at Fifth Avenue between 70th and 71st streets. Hastings’s Neoclassical solution comprised a skylit gallery along 71st Street, a linear assemblage of family rooms along Fifth Avenue, and a porte cochère at 70th Street that allowed carriages to proceed toward an open court to the north.

When the classically trained John Russell Pope turned the Frick into a public museum, he replaced the porte cochère with an entrance on 70th Street, and covered the open court with a skylight to create an enclosed garden with foliage, fountains, and paired Ionic columns. He also added a skylit Oval Room, East Gallery, and a circular music room along 71st Street. Finally, Pope designed a nine-story Art Research Library on 71st Street, adjacent to the galleries.

Owing to his reliance on similar architectural motifs and choice of Indiana limestone, Pope’s expansion appeared seamless, and, when it opened, Art News commended the Frick for changes that converted “a handsome private dwelling to an efficient museum building.” Lewis Mumford, however, was not thrilled: in The New Yorker he complained about the over-regulated public circulation within the rooms. Moreover, he would have preferred the bare backgrounds of a modern building to the domestic setting, as if anticipating the Frick’s later stunning installation, also by Selldorf, of part of its collection in Marcel Breuer’s stolidly modern former Whitney Museum on Madison Avenue, while the expansion was underway, from 2021 to 2024.

From 50 visitors a day in 1935, attendance grew over the years, although it meant staff offices took over the former bedrooms and private quarters on the second floor. A velvet rope kept museumgoers from ascending the grand stair, yet made them long to see what they were missing.

The Landmark Preservation Commission’s designation of the Frick Collection and the Art Research Library in 1973 did much to assure the public that the Frick was safe from thoughtless incursions. But the pressure didn’t stop. By 1977, there were 1,500 visitors a day. In need of enlarged coat closets, ticketing space, and seminar rooms, museum management enlisted architects Harry Van Dyke, John Barrington Bayley, and G. Frederick Poehler to design a pavilion along the east flank of the museum, on 70th Street. The new structure, inspired by Jules Hardouin-Mansart’s Grand Trianon at Versailles, was one story aboveground, with two levels of seminar rooms (eventually turned into temporary-exhibition galleries) and other services below grade.

As an extra bonus, the Frick commissioned British landscape architect Russell Page to create a small garden next door, which would be built on a roof over storage spaces. Van Dyke, Bayley, and Poehler wisely clad the pavilion and garden walls in the same Indiana limestone as the existing complex. Nevertheless, their interior treatment of the reception hall, according to Progressive Architecture, drew criticism about the overwrought and heavy-handed plaster ornament. Others wondered if a small garden to the east was even necessary, since the Frick had a lush lawn on Fifth, which in turn faced Central Park across the street.

The 70th Street Garden’s raison d’être would be brought up again when the impulse to expand cropped up in an aborted proposal in 2014. The previous year, attendance had grown to about 1,800 a day. The scheme, by Davis Brody Bond, proposed adding a six-story building to the east, which not only called for tearing down the 1977 addition but covering over the Russell Page garden. Although the architects had sensitively enclosed a loggia along the north side of the West Gallery in 2011 to display decorative objects, this project was different. Now Davis Brody Bond’s scheme for a new stepped structure of 60,000 square feet projected a bellicose presence along 70th Street. Vitriol and venom spewed forth from preservationists and historians, as well as from RECORD.

The brouhaha convinced the Frick, under director Ian Wardropper, to seek a more sympathetic solution. By 2017, the museum chose Selldorf Architects, whose principal, Annabelle Selldorf, was known for her minimal designs of art galleries and cultural buildings. Selldorf’s elegant renovation of the nearby Neue Galerie (formerly a mansion also designed by Carrère & Hastings) proved reassuring. In recent years, Selldorf has become the go-to architect for highly publicized (even controversial) renovations and expansions of museums such as the National Gallery’s Sainsbury Wing in London, opening this month, and the Museum of Contemporary Art San Diego in La Jolla, California (2022).

Selldorf’s proposal kept the 70th Street Garden, renovated and restored the existing rooms, and remodeled the 1977 reception hall. The expansion also added offices, a shop, a café, and conservation lab, arranged in two discrete blocks connected by glazed links on the second, third, and fourth floors. The taller of the two—matching the height of the Pope library—is stepped back, filling an open space 22 feet deep on the site north of the garden. “We used every square inch of those 27,000 square feet,” jokes Selldorf. Indiana limestone would clad the exterior in accordance with the existing museum, minus the classical cornices, columns, and moldings. Because of the variegated ensemble, Selldorf’s exteriors, seen across the garden from 70th Street, do not read as a “facade.” Instead, they are reticent. Perhaps this is a good thing, if a little bland.

Very astutely Selldorf did not do what many architects have done when undertaking a renovation: design a new main entrance, ostensibly to improve circulation, so that all attention is diverted from the historic building. (The Morgan Library & Museum in New York and the National Gallery’s East Wing in Washington, D.C., illustrate this point.) Selldorf kept Pope’s entrance, and for that we are grateful. The circulation remains the same too, taking visitors from the entrance hall either into the original dining or living rooms, and others on the west, or straight ahead to the Garden Court and galleries along 71st Street.

Not only does Carrère & Hastings’s magnificent main stair remain intact, it is no longer roped off to the public. Now it beckons the museumgoer to ascend to the second floor, where Selldorf and BBB turned former offices into art galleries by restoring the architectural elements, fabrics, and finishes evocative of the Frick family’s bedrooms and private quarters. The Rococo Boucher panels that had adorned Adelaide Frick’s sitting room—but were later moved downstairs—have now been returned to their proper place.

The restoration and refurbishing of the rooms, the many galleries, and the Garden Court required labor-intensive replacement of wallcoverings of silk and wool, new painting and plasterwork, and upgrades to skylights and lighting, not to mention inserting new mechanical systems, ADA ramps, elevators, and restrooms.

The skylights over the galleries and the Garden Court demonstrate the intricate improvements undertaken. Original single-paned ones led to condensation and leaks; now a complex tripartite system is in place. The first component is an outer skylight (comprising three layers of glass; an air space separates the topmost from the bottom two, which are laminated together). Second is the “attic” space, containing structural steel, a shading system, and supplementary LED bulbs. The third is the laylight, visible to the visitors, formed of an upper-level acrylic panel, then an air space, followed by another layer of acrylic. The Frick’s antiquated electric lighting in its chandeliers, pendants, and sconces has been rewired, and its incandescent bulbs switched out for LEDs (3200 Kelvin for a warmish light).

While so many moves are sympathetic to the existing architecture, the project has not been without controversy, particularly when Selldorf proposed demolishing the circular music room to put temporary-art galleries in its place. Because the Frick museum management found the music room acoustically dead and too small (only 149 seats), Selldorf decided to carve out a lecture and music hall for 220 seats under the 1977 pavilion and the 70th Street Garden. Amid much moaning from those keen to keep Pope’s circular space intact, the plan went ahead.

While this observer misses the music room, the rectangular temporary galleries, 14 feet high with oak door surrounds, are a vast improvement over the mingy low-ceilinged spaces that served as temporary galleries under the 1977 Reception Hall. However, not until June, when the first exhibition (of Vermeer’s work) is installed, can an accurate assessment be made. To her credit, Selldorf’s fluidly curving, white-plastered auditorium, with a sinuous, crisply edged proscenium, is outstanding. (Again, acoustic assessments must wait for the concerts to begin.)

The remodeled Reception Hall that replaced the 1977 one kept the same footprint, but there are major changes. Selldorf inserted a new stair to provide circulation to a new shop and café on the second floor, and to a lower cloakroom level and, below that, the auditorium. The five-story stair’s panache owes much to its flamboyant use of Breccia Aurora Blue marble for thick cantilevered treads and landings, and its elaborate handrails of brass and black steel. Yet, because of its placement, away from the earlier architecture, it doesn’t detract attention from the stately main stair. Nevertheless, it comes as a surprise for those expecting something more like Selldorf’s Breueresque concrete staircase in her David Zwirner Gallery on 20th Street in Chelsea.

In order to create the shop and second-floor lobby above the 1977 Reception Hall, Selldorf raised the gable of the pavilion 7 feet and lowered the ceiling of the Reception Hall so it stops just at the top of the arched French doors opening onto the 70th Street Garden. In making these changes, the architects stripped the interior walls of their plaster ornament (the ornament considered so heavy-handed in 1977) and clad the surface with Indiana limestone to match the exterior. The starkness of this new wall and undercooked detailing contrasts almost too emphatically with the razzle-dazzle stair: an earlier rendering shows a niche carved between the French doors—but space for the ductwork was needed.

An education center on the main floor—a new element in the program—overlooks the garden from the north. Deep-set windows with walnut paneling and baseboards give the space a handsome, traditional tone. Above, the second floor’s skylit lobby and shop, with wood paneling and bronze curtain walls, inject stringently elegant notes to the new addition. Nearby is the café, where Selldorf’s interior architecture, including the off-white Italian limestone walls and the marble herringbone floors, are supplemented by designer Bryan O’Sullivan’s banquettes and polished-walnut bar. A mural of a landscape along the upper part of the room, painted by Darren Waterston, adds an East Asian sensibility to the otherwise 1940s-moderne ambience. Above the café, on the third floor, the Renaissance Revival library has been restored, while an up-to-date conservation laboratory has been added to the fourth.

The circulation within the complex (and between the two new blocks) now allows staff and visitors to find galleries, offices, and the research library without going outside or getting lost. Crucial to the sense of orientation, however, are glimpses of the 70th Street Garden. Ironically, this element, which remained because of preservationists’ efforts, now helps visitors know where they are inside. More important is perception of the exterior along 70th Street. Because the new Selldorf structures at the north of the garden are rather mute, visitors arriving from Madison Avenue focus on the older, lower Frick buildings. The garden offers a now necessary void that gives the classical architecture of the existing ensemble the space to stand out, so the Frick-mansion museum remains the dominant figure in this gestalt. And that is a good way to expand.