The Edens theater in Illinois is the largest single h/p shell in the United States, measuring 159 feet between working points at the abutments and 221 feet from tip to tip. In addition to providing much to be desired column free interior space for 1350 seats, the h/p roof shape is expected to impart excellent acoustical characteristics to the building. The underside of the roof has been left exposed, while the exterior material over which a spray coat of whit paint has been applied. The abutment walls and the foundation pads on which they rest are post-tensioned. Edge beams for the structure are 30 inches wide and they vary in depth form 22 inches at the tip to 58 inches at the abutments. The theater was designed by Perkins and Will.