“It’s still a sausage factory here,” explained Elizabeth Diller, Diller Scofidio + Renfro (DS+R) principal, of the work in progress during last week’s hard hat tour of The Broad Museum, a 120,000-square-foot, three-story contemporary art museum built by philanthropists Eli and Edythe Broad in downtown Los Angeles.

Workers climbed atop scaffolding, structural innards lay bare on the walls, and a fine dust settled on the concrete floors, but one could already see glimpses of what was to come.

Sited beside the Walt Disney Concert Hall, DS+R (with Gensler as executive architect and Matt Construction as general contractor) adhered to a “veil and a vault” theme that would not clash with its iconic neighbor while still revealing the interplay between art exhibition and storage. “Where the Disney Hall is shiny and smooth, the Broad is porous and light,” said Diller. Her firm won the commission to design the museum in 2011.

The “veil” is a honeycomb-like structure made of 2,500 fiberglass reinforced concrete (GFRC) panels that cover all five sides of the box-shaped museum, creating a porous facade and a skylit ceiling—the biggest challenge the team faced in construction. The architects were able to envision the scheme using 3D modeling software CATIA. The facade lifts up at two corners on the ground floor, drawing visitors into the museum lobby and a bookstore.

At the entrance, visitors are also immediately introduced to the “vault,” a hovering concrete slab that cantilevers 45 feet over the lobby, which leads to the 15,000-square-foot gallery for temporary exhibitions and three circulation options to the top floor: a glassy, cylindrical elevator; a 102-foot escalator; or a stairway. The four flights of stairs punctuated with two viewing portals provide a glimpse into the museum’s archiving and storage activities.

The second floor houses administrative offices, archives visible from the stairway, conference rooms, and a multi-purpose space called the Oculus Hall. One wall will have a half-spherical indentation where the "veil” will suddenly be sucked in “like water being poured onto a surface,” said Diller. This floor also holds most of the mechanical systems.

On the third floor is the pièce de résistance, a nearly one-acre, column-free gallery space with a 23-foot-high ceiling suffused in natural light from 318 skylight monitors oriented north. Temporary exhibition walls could be erected and re-arranged using a 10-by-10-grid system on the floor with structural connection points.

Meanwhile, plans continue to evolve. Designs for a plaza on the southwest corner of the museum is still in the works. The Broad is scheduled to open late 2014. It was announced during the hard hat tour that the museum will be free to the public.