The Wrapper Diller Scofidio Renfro chose to leverage Boston's HarborWalk as much as possible by weaving it through the building. The firm's strategy was to take the boardwalk, property of the citizens of Boston, and metaphorically extend it into the new building as a pliable wood surface that defines the major public spaces. This continuous surface penetrating in and out again serves to transform the harbor view into a theatrical backdrop for the stage. The intended reading of a folded HarborWalk surface is achieved through the consistent use of one wood species, a South American mahogany. That mahogany is milled into planks for the exterior decking; milled as tongueand- groove boards for the sprung floor of the theater stage; milled into veneer and laminated over fire-rated MDF at the interior walls and ceilings; and edge-routed for concealed fasteners at the underside of the exterior cantilever.
The architects selected an interior wood stain to match the weathered finish of the exterior wood.
Theater: Curtain Wall The north and west walls of the theater are uninterrupted glass surfaces. As principal Charles Renfro explains, "We wanted to work with the view, but not let it take over the building." The curtain-wall design went through several iterations, starting with a sheer glass-fin structure, with an additional layer of glass at the inner face of the fins to decrease noise from jet traffic at nearby Logan Airport. During the later stages of design, acoustic engineers decided the noise infiltration was insignificant, and the second glass layer was eliminated. (Ultimately, the glass fins were replaced by aluminum supports as a cost-saving measure.) Nonetheless, each of the insulated glazing units that make up the single glass layer is composed of two thicknesses of glass, arresting different frequencies of sound as they pass through the wall.
The horizontal header and sill plates of the curtain wall were buried above and below their adjacent surfaces, allowing the wrapper to appear to penetrate the walls. To maintain the drama of the interior, structure along the north and west walls was kept to a minimum. The theater is suspended from above by mega-trusses. Parallel to each curtain-wall mullion is a steel hanger that also provides tracks for scrim and blackout shades. The shades can be controlled to meet performance needs_from full transparency, to filtered light, to total blackout.
Interior Stairwell The egress stair serves double duty as the main public stair. Shaping the stairwell is a segmented, planar surface that seems to unfurl like a roll of curling ribbon. The painted steel plates function as a guardrail and are also bent to produce rigidity for the stair stringer and handrail supports. Risers are painted steel pans containing pouredin- place concrete treads with a matte sealer.
The plane of the guardrail is illuminated by a continuous vertical lighting element of fluorescent fixtures, which are housed in aluminum extrusions and supported by a steel tension rod and extend the entire four-story height.
Gallery Ceiling and Skylights The ICA's previous home was an urban infill building dating to 1866 with galleries distributed on four levels. By contrast, the new ICA was designed with flexible, column-free galleries on a single floor. Placing the galleries at the top of the building allows the exhibition space to be illuminated by uniform, diffused daylight through a system of skylights. The skylights are equipped with motorized shades to regulate light levels. Working in collaboration with electrical engineer Andy Sedgewick of Arup London on the daylighting system, the design team determined the optimum height of the gallery to be a minimum of 15 feet, 6 inches. The monolithic ceiling diffuses light through a scrim made of a taut Trevira fabric. Above it, sawtooth skylights admit light into a 6-foot-deep loft that also contains mechanical ducts, electrical lighting, and a kicker panel to improve light distribution. Electrical uplights in the loft simulate the same quality of light at night. Although the ceilings appear plain and unencumbered, they are anything but. A 6-foot-by-12-foot aluminum grid holds the demountable scrims and also serves as lighting tracks, an overhead structural support for temporary dividing walls, and an organizational spine for sprinkler heads and smoke alarms. The polished concrete floor is subdivided into corresponding 12-foot-by-12-foot bays, with structural and electrical nodes centered in each one. The key feature of the structural system is a series of four mega-trusses-each 175 feet long and 24 feet high-that allow for the dramatic cantilever. Three of the trusses run approximately north-south, whereas the fourth is angled slightly to conform to the building footprint. At the core, the two center trusses are spaced only 24 feet apart.
The outer trusses are roughly twice that distance from the inner ones, which creates the loftlike gallery spaces. The heaviest steel member is a W14 x 455 beam, which is located at the top chord sp
Founder's Gallery The Founder's Gallery is a crossover space that spans the full width of the building's north face. By connecting the main east and west galleries, the linear room is woven into the choreography of the art-viewing sequence. The gallery's glass curtain wall-which stretches floor to ceiling, revealing a panoramic view of Logan Airport, Bunker Hill, and Boston's business district-is composed of cantilevered laminated glass fins with point support fittings.
Founder's Gallery The Founder's Gallery is a crossover space that spans the full width of the building's north face. By connecting the main east and west galleries, the linear room is woven into the choreography of the art-viewing sequence. The gallery's glass curtain wall-which stretches floor to ceiling, revealing a panoramic view of Logan Airport, Bunker Hill, and Boston's business district-is composed of cantilevered laminated glass fins with point support fittings. The wall was designed and tested in a full-scale mock-up to ensure its ability to withstand high winds whipping in from the Atlantic Ocean.
The wall was designed and tested in a full-scale mock-up to ensure its ability to withstand high winds whipping in from the Atlantic Ocean.
Mediatheque In conceptual terms, the Mediatheque is a piece of the gallery space that folds down from the cantilever. Here, visitors can access curated shows on the web as well as the ICA's growing database of digital artworks. The tiered space has 16 iMac stations, each of which is fabricated with a rotating stainless steel arm to accommodate two users. Artificial lighting, placed in coves below the benches and stairs, eliminates glare on the computer monitors. Noise is absorbed by the acoustical panel-andplaster ceiling. The lower end of the 1,100- square-foot space is capped by wall-to-wall, floor-toceiling glass. This minimally detailed window offers tight views of the foreground water below-all context stripped away by the solid walls, ceiling, and floor. Avoiding the thicker sightlines of insulated glass units, which have opaque spacers, the architects detailed the window using two planes of butt-glazed laminated glass with a heated air cavity between. To eliminate condensation in the winter, the air cavity is maintained at a higher temperature than either the Mediatheque interior or the exterior. Natural and digital phenomena blend in this space to induce a tranquil atmosphere, "like watching a campfire," says Scofidio.
Yet the mood of the room changes constantly with the passage of the sun and shifts in wind and weather conditions that can render the harbor placid or churning.
