British architect David Chipperfield is known for his elegant, almost minimal, typically rectilinear compositions. In the middle of the continental United States, Iowa might be classified as a flat expanse of farmland lightly touched by the great American grid of north/south and east/west coordinates. Now Chipperfield has completed not only his first but his second freestanding building in the United States. And both are in Iowa.
Des Moines, Iowa’s capital, has the corporate towers one expects in a city of this importance. The new Central Library starts near the base of some high-rises, then stretches parallel to adjacent low-rise buildings and parking lots to point westward across a public park. “Parallel” is imprecise as the library - atypically for a Chipperfield design - is polygonal, aformal, perhaps even biomorphic.
Beneath a uniform flat roof, the walls of the library extend as a contiguous membrane of identical glass panels, taut and frameless. In daylight the building glows a metallic honey colour; at dusk, when illuminated from within, the interior life of the library is exposed to passers-by. These panels - a German system known as Okalux - comprise three layers of glass with a sheet of copper mesh between the outermost and middle layers. This metal filament deflects excess solar heat and glare. It also, of course, gives the institution a striking monolithic identity.
The unusual shape of the building is determined not only by contextual issues of adjacency and access but by an absolute iteration of the vertical Okalux module (1.2 x 4.0 metres high) about the entire perimeter. Adhering to this pragmatic rule, Chipperfield avoids the half-module or infill sliver panel. The façade is two modules high, expressing the two-storey interior. The panels sit on a slim concrete plinth that in turn hovers just above the ground; they also terminate flush against the sky.
The library might be read as a three-pronged star extending asymmetrically from a central 9 x 9 metre grid of concrete columns. Obversely, it can be interpreted as an orthogonal box impinged upon by specific realities. The long northern flank inflects inward to allow automobile access to underground parking and a drive-up service window. The building mass cranks to evade a former Masonic hall in the southeast corner; then opens up to the west and the new park (an uninspiring design by the Oregon practice Zimmer Gunsul Frasca). The resultant oblique angles create dramatic reflections across the facades.
Pedestrians pierce the building between the Masonic hall and the park, entering a porch screened by sliding glass doors. They can enjoy a café and public meeting rooms in the south wing, or turn north into the library proper and the librarians’ white Corian desk. This is a very public mingling space. Pedestrians can also enter from the north next to a highly visible, glazed space intended as a bookstore but currently serving as a small gallery. There is one chunky, black terrazzo staircase at this internal crossroads. A second staircase serves the children’s wing, to the west.
Chipperfield selected blue, green and yellow tones as accents in the south, east and west wings respectively; he also designed the lounge chairs, stools and side tables. Ceilings are of exposed concrete with suspended, linear light fixtures. If not concentrating on books or the many computer screens, library users benefit from the unobstructed views out through the Okalux walls to the cityscape and vegetation outside. The entire roof is planted with sedum so that, from adjacent high-rises, the library appears to fuse with the park.
The Figge Art Museum occupies a splendid site in Davenport on the eastern edge of Iowa. This is the state’s serpentine border following the broad Mississippi river on its journey from northern Minnesota to the Gulf of Mexico. Chipperfield’s museum, a diaphanous box of milky glass, takes advantage of this prospect. It also seems conscious of the many agricultural silos and mills whose silhouettes are a memorable presence in the flat Iowa landscape. Indeed such artefacts of the American industrial vernacular have long impressed European architects.
The building is again monolithic and vitreous, but here Chipperfield has maintained his customary rectilinearity. The museum extends the length of its block parallel to the riverside park, thus freeing up a large forecourt to the city’s streets to the north. The south facade has a long indentation to direct visitors in and up to the River Drive entrance. From the city, visitors approach across the new sculpture forecourt as side streets slope down towards the Mississippi. Then, to take advantage of views, a central section of the building expands upwards as a svelte tower flush with the longer facades.
These facades are composed of fritted glass panels laid horizontal and flush to all edges and parapets so that the building appears both cool and geometric. The sun and sky introduce games of light and shadow as metal panels and large windows in an inner skin introduce further nuance. Certain zones of the facades then switch their legibility at dusk, clearly becoming voids contained within the block. Such is the elegant restaurant in the southwest corner; and a multi-height space - a loggia, almost - in the south face of the tower.
As at the Des Moines Central Library there is more than one entrance, and the foyer space works something like a small interior piazza. Whereas upstairs the galleries have wood floors, white walls and white flush ceilings, the entry-level public spaces have dramatic inky black floors and linear ceiling coffers that extend into a barroom to one side. There bright red walls, red upholstered benches, and strips of horizontal mirror supply a satisfying aesthetic shock before visitors continue into the light-filled restaurant overlooking the Mississippi.
Throughout the well-proportioned interior Chipperfield favours tall and slender portals, doors, and even door handles. The piano nobile contains permanent exhibition galleries to the west and extensive art studios, offices and education spaces to the east, where transparent glazing on the inner skin gives the facade a series of horizontal accents. The raised portion of the monolith houses temporary exhibitions connected by a complex stair hall or winter garden - the glazed loggia visible from outside. For both Iowa buildings, Chipperfield has achieved dignified civic space within a distinctive, tailored volume.