The structural condition as challenge for the deconstruction planning. Until now no mandatory guidelines for the structural planning of the deconstruction of existing concrete structures are introduced by the authorities, which assist the planning engineers in the evaluation of these existing or damage structures. Often complex structural states of deconstructions have to be calculated, which depend on the knowledge of the actual structural condition. Therefore the only source of information is given by the existing documents, which often don't represent the actual state. To reduce the risks and to increase the planning and tender security, diagnostic investigations offer a big potential. Because not all information, as e. g. the knowledge about the possibility of a subsequent anchorage of cut prestressed tendons can be evaluated in advance of a deconstruction, further experimental investigations are necessary. As yet no technical or contractual rules are defined. The paper gives an overview of practical experiences and possible potentials of these experimental investigations.