Development of the site is significant to the planned northerly expansion of Principal's campus and to the future growth of downtown Des Moines. Principal's home office building, Corporate Square, is located directly south of the site. The design approach was to develop an appropriate response to building requirements, create a "public" plaza, create a visual and physical connection between the "downtown" on the south and the area to the north, maintain visual continuity of existing street spaces, and exhibit sensitivity to the scale of the local context.

The building plan developed as a broad footprint located at the north end of the site. Large floor plates allowed the mass of the building to be reduced to a height of eight stories and conform to the scale of the surrounding buildings and open space. In plan, the building may be interpreted as a long linear element folded into the shape of an "N". Levels 6, 7 and 8 of the building are contiguous floor plates, however, Levels 1 through 5 are interrupted at approximately mid-building creating a Gateway ninety feet wide and five stories high through the building. A transparent glass bridge connects the east and west sides of the building at Level 3 without visually obstructing the Gateway.

The Gateway becomes a pedestrian "street" physically and visually connecting the area north of the building with the plaza and downtown area south of the building while the building's configuration defines street spaces on the north, east, and west sides. Viewed from the plaza, the building becomes a "wall" defining the north edge of the plaza with the roof height trellis creating a "forecourt" which provides a transition between the plaza and the building's entrances in the Gateway. The hard and soft elements of the plaza extend the building's geometry over the site establishing a defined sense of order.

The facades respond to the surrounding context and the structural frame of the building. The north and south facades are aluminum framed glass curtain wall developed in modules defining the structural bays. Floor-to-ceiling vision glass provides open views from the interior and transparency from the exterior. Inset window areas adjacent to the columns and reveals in the curtain wall result in shadows adding overall texture to the glass walls. Frit patterns applied to the lower part of vision glass and to floor-line spandrel glass provide added detail as the facades are approached. The glass spandrels and aluminum spandrels at alternating floor lines define the horizontal linearity of the building. The east and west facades, clad with limestone panels, provide visual and historic continuity with the limestone clad Corporate Square building and nearby masonry wall buildings. Vision areas in the east facade are horizontal "ribbons" of glass between limestone spandrels, vision areas in the east facade are "punched" openings in a limestone wall. A pattern of diagonal reveals cut in the face of the limestone adds texture to the smooth stone panels.

The design of the plaza is intended create a public urban space which is both civic plaza and garden. The paved areas of the plaza contain a raised lighted stage with mist fountain, an area adjacent to the cafeteria suitable for outdoor dining, and a shade garden of mature Burr Oaks. A crabapple "orchard" on the north side, a rock garden in the Gateway, a grassed area with limestone seatwalls and flower beds, a bermed "great lawn" and terraced plantings provide visual diversity in the urban plaza.