During the Second World War, the Nicolaihaus suffered severe damage. Reconstruction work on the façade began in 1952. The GDR Institute for the Preservation of Monuments moved into the renovated interior, which was specially redesigned for this purpose. The side wing, which had been destroyed during the war, was also rebuilt. Extensive restoration work was carried out between 1974 and 1984. During this process, the Weydinger staircase, a classicist structure that had previously been saved from the Ermelerhaus before it was demolished, was integrated into the transverse wing.