The structural implementation of the program’s claim, however, met with difficulties: Stubbins’s original design was for a free-floating roof supported by only two pillars. The idea of a roof resting only on a few points corresponded to the zeitgeist of organic building of that time. In 1953–1956 Eero Saarinen had constructed a roof for the Kresge Auditorium of the Massachusetts Institute of Technology in Cambridge that rested only on three supports.

[…] But the freestanding roof designed by Stubbins for the Congress Hall was not feasible. They stuck to the idea but an auxiliary structure was needed. The support of an additional ring beam over the outer walls of the auditorium was necessary to shore up the roof on its two points. This structure not only found advocates among architects, but also fierce critics. “Never before has there been a suspension roof with such expensive and cumbersome construction,” wrote Frei Otto in 1956, who had, however, built similar roof shapes as early as 1955 in his Music Pavilion in Kassel. There were safety concerns about the technique given the extremely complicated and delicate structure of the Congress Hall roof.