During the first decades of the twentieth century, construction technology experienced rapid developments, which also affected industrial buildings. This paper demonstrates this evolution between 1905 and 1912 through the case of the Rjukan and Notodden UNESCO World Heritage site in central southern Norway. The site was established for the purpose of producing synthetic nitrogen fertiliser by the company Hydro. There, building systems changed from timber frames with brick infill to pure brick bearing walls and finally to more sophisticated wall-braced cage buildings where steel was incorporated. Increasing the structural capacity was the answer to the growing demand for higher and larger industrial buildings. This case study presents the characteristics and establishes an initial account of the types of construction systems. Embedded steel that is concealed within brickwork can be subject to corrosion and compromise structural integrity. Studying these systems and materials in greater detail and identifying conservation issues will support future repair work. The studied buildings reveal also that used systems were not unique to this remote mountain area, but the technology used was in line with developments in leading industrial nations around the world. This places the site also in an international context of architecture and engineering history.