When the trustees of the Des Moines Art Center selected I. M. Pei to design an addition to the building in 1966, their choice was one of deference to the architectural integrity of Saarinen’s building. The assignment from the trustees was daunting: to provide space for the display of monumental sculpture, with gallery heights as much as twice those of the existing building. In addition, there was need for a larger auditorium to serve an increasing audience. These demands risked a new building which would tower over the Saarinen, creating an aesthetic conflict between the low natural masses of the original building and the more severe forms for which Pei was becoming famous.
To resolve this conflict Pei utilized the topography of the site, which slopes down southward from Saarinen’s open courtyard. By nestling the large volumes of his building against this slope, he could match the height of his building to that of the Saarinen galleries and close the courtyard with a glazed sculptural facade and a new reflecting pool. Only the largely transparent butterfly roof of his new gallery would soar above this height.
The materials of the new building would simultaneously challenge and accept the existing materials palette. Saarinen’s natural stone cladding would be juxtaposed against the concrete walls of Pei’s design. The new walls, however, would be bush-hammered, roughening the crystalline concrete volumes and, also, revealing the larger Lannon stone aggregate within the concrete, thus giving the new walls a visual connection to the older cut-stone walls.
The dominant effect of the completed building is largely interior, a play of solid and void, enclosure and release, lightness and mass. The newly enclosed courtyard is simultaneously a harmonious volume and a juxtaposition of the solidity of the Saarinen building and the sculptural playfulness of the Pei. Entering the soaring upper gallery from narrow halls on east and west, the visitor is offered a breathtaking spatial experience. The concrete “wings” of the butterfly roof hover overhead, opening to admit abundant natural light which cascades over the roughened concrete walls. Across the expanse of the upper gallery, the lower gallery opens downward and outward to views of the Greenwood Park Rose Garden. This eloquent and masterful building, completed in 1968, profoundly enhanced the Art Center while respecting the materials palette and scale of the original Saarinen. Upon its completion the addition was almost invisible from Grand Avenue. The Pei building extended the institution’s reputation for commissioning only the most talented contemporary architects, working at the top of their game.
Written by Tim Hickman