Since 1955, the Weida dam, together with the Zeulenroda dam, has ensured water supply, flood protection and minimum water flow in eastern Thuringia. For the design and supervision of its general overhaul in accordance with the principles of monument conservation, Fichtner Water & Transportation were charged to manage a joint venture. In addition to the general overhaul, the raw water pumping station at the foot of the dam had to be transformed into a hydroelectric power plant allowing the use of the dam’s hydropower potential. All structures had been built with slag sulphate cement which is absolutely incompatible with all construction materials based on Portland cement. This required the customised planning of materials procurement, standardisation/approval procedure and quality assurance.