Ambitious Redesign of MoMA Doesn't Spare a Notable Neighbor A rendering of the planned 54th Street entrance for the Museum of Modern Art. Diller Scofidio + Renfro The Museum of Modern Art unveiled on Wednesday a sweeping redesign of its Midtown building, featuring a retractable glass wall, new gallery space and the opening of its entire first floor, including the beloved sculpture garden, free to the public. It is unclear whether this grand, ambitious plan will be enough to quell protests over the long-contemplated and controversial part of the museum's overhaul: the razing of its next-door neighbor on West 53rd Street, the noteworthy, if idiosyncratic, former home of the American Folk Art Museum. MoMA announced in April that it planned to demolish the folk museum, despite the building's well-regarded designers and its striking bronze facade. After protests from architects, urban planners and preservationists, MoMA officials said they would review that decision. But museum officials said on Wednesday that keeping the folk museum, built in 2001 and bought by MoMA in 2011, was simply impossible, and they focused on the benefits of the new design that came about during the review. A rendering depicts the view of the new complex from 53rd Street. "It's a very nice gesture of a kind of new ethos: To make publicly accessible, unticketed space that is attractive and has cultural programming," Glenn D. Lowry, MoMA's director, said. The architects of the folk museum, Tod Williams and Billie Tsien, protested the most recent decision in a statement. "This action represents a missed opportunity to find new life and purpose for a building that is meaningful to so many," the architects said. The inability to experience the building firsthand and to appreciate its meaning from an historical perspective will be profoundly felt. MoMA plans to start construction this spring or summer and to finish the project in 2018 or 2019. Despite the plan's broad scope, the museum said it could not yet provide a budget, making the viability of the redesign hard to measure. MoMA officials said they would need to raise all the money privately because the museum is not a city-owned institution. "This is now a much bigger project than we had envisioned," Mr. Lowry said. We have to figure out how to cost it out. The overhaul seeks to address some of the criticisms leveled at the museum since its $858 million overhaul by the Japanese architect Yoshio Taniguchi just nine years ago. Common complaints are that the 2004 redesign appears cold and closed off to the general public; its lobby is chaotic and overcrowded; and it takes too long to reach the art. Diller Scofidio & Renfro, the architectural firm hired by MoMA to evaluate whether the shoebox-shaped, 40-foot-wide folk art building could be incorporated into a renovation, said the decision was arrived at after intensive study. The broad plan was presented to some members of the media on Tuesday and Wednesday. "It's not for lack of trying that we find ourselves at the same pass," said Elizabeth Diller, a principal at the firm. We can't find a way to save the building. Plans for the Museum of Modern Art According to plans released Wednesday, much of the ground floor of the Museum of Modern Art would become open to the public. The museum expects the project to be completed in 2018 or 2019. Three floors of existing gallery space will be extended here New Art Bay with exhibition and performance space above Ticket scanning will occur at multiple points The decision to abandon the building was a matter of function, not aesthetics, Ms. Diller said. Because the floor plates support the facade, a reconfiguration would require much of the building to be dismantled and reconstructed. "To save the building, we had to lose too much of the building," Ms. Diller said. You pass a tipping point where there's not enough of the original structure to actually maintain its identity. The strain on the firm as it proposed destroying another firm's work seemed visible. "It's very hard to make peace with yourself," Ms. Diller said, "to advocate for taking down a building that's only 12 years old." Mr. Lowry said that he had notified Mr. Taniguchi of the prospective changes to his building. "You build something and you start to realize some things work well, some things are O.K. and some things can be improved," Mr. Lowry said. The architects plan to use the former folk art museum site for what they envision as the MoMA of the future, creating a ground-floor area they call the Art Bay. That space would be fronted with a sheet of glass that could be raised to open the gallery to the street. The Art Bay would be a flexible space for exhibitions and performances, similar to the courtyard at MoMA PS1, an affiliate of MoMA in Long Island City, Queens. This is in keeping with the intentions of MoMA's founding director, Alfred H. Barr Jr., to establish an art space "directly connected to the street," Mr. Lowry said. Above the Art Bay, and connecting to the museum's fourth level, would be the Gray Box, so named because it combines the attributes of a white box gallery with a black box performance space. It would have acoustic absorption panels to accommodate the museum's growing interest in performance art, and its interior would be visible from the street. Redeveloping the folk art museum's site would link MoMA's existing galleries to a planned 82-story residential tower just west of the folk-art site, designed by the French architect Jean Nouvel. The tower, being developed by the Houston-based Hines - would include exhibition space for the museum. A current view from 53rd Street. The redeveloped folk art museum site would allow MoMA's second, fourth and fifth floors to flow continuously from one property to the next. The second-floor galleries are double height. Although MoMA's 2004 renovation added space, the museum said it still needed more room. It had projected annual attendance of about 2.2 million in the Taniguchi building. Instead it has reached 3 million in a space of 125,000 square feet. The Metropolitan Museum of Art, by comparison, has 6 million visitors and 2 million square feet. "Anyone who's been in the building knows how crowded the galleries are," Mr. Lowry said. The museum has also done some major collecting in the past decade, Mr. Lowry said; acquiring Frank Lloyd Wright's archive; the Daled Collection of Conceptual art; the Shunk-Kender Photography Collection; and the Gilbert and Lila Silverman Fluxus Collection of about 3,000 items. "The collection started to burgeon, so there was increased pressure," Mr. Lowry said, adding, "We don't have all of our "A" collection on view." The expansion would add 15,500 square feet of gallery space in the folk art site at 45 West 53rd Street, and 39,000 square feet in the Nouvel tower. The redesign intends to improve the museum's West 53rd Street entrance - "You don't know where to enter," Ms. Diller said - giving it a new exterior canopy and an interior double-height lobby, like its West 54th Street counterpart. It will also establish a new east-west connector by opening lobby walls. Ticket scanners have already been moved deeper into the lobby, a change MoMA implemented at the architects" suggestion. The Abby Aldrich Rockefeller Sculpture Garden, recently opened to the public for an hour at 9:30 a.m. on a trial basis, will become accessible through an expanded 54th Street entrance as well as through the museum. But the former folk art museum will be gone. After study, Ms. Diller said her firm determined that the folk art museum was "a bespoke building that was made specifically for the scale of the art that was going to be shown there." Ms. Diller said that she had personally informed Ms. Tsien and Mr. Williams of her firm's conclusions. "It was just a kind of impossible task," she said. We really, really tried for them.