The old office building with its representative façade on Lösorter Strasse opened in 1906 was initially the main reception building and accommodated the Board room. It was also used to pay wages to the workers. Extensions were added and uses changed until the early fifties. When the new office building on Emscherstrasse had been completed in 1953, its use changed again. Wash and locker rooms were integrated, a cafeteria for the workers was built, a surgery was provided and labor representatives received their own rooms. Today, the German Youth Hostel Association runs a 140-bed hostel in the building.