In the late 1920s Stam was part of the team at the New Frankfurt project. In 1930 Stam became one of the 20 architects and urban planners organized by Frankfurt city planner Ernst May who traveled together to the Soviet Union to create a string of new Stalinist cities, including Magnitogorsk. The "May Brigade" included Austrian architect Margarete Schütte-Lihotzky, her husband Wilhelm Schütte, Arthur Korn, Erich Mauthner and Hans Schmidt. Stam was there in February 1931 to participate in the struggle to build rational worker housing from the ground up, an effort ultimately defeated by adverse weather, corruption, and poor design decisions. Stam moved to planning activities in Makeyevka in Ukraine in 1932, then to Orsk, with his friend Hans Schmidt (again) and with Bauhaus student and future wife Lotte Beese, then to the copper-mining Soviet city of Balgash. Stam returned to the Netherlands in 1934.