Project for reconstruction and / or reinforcement of existing buildings and facilities in Bulgaria have to be prepared on the basis of a structural survey and expertise based on the existing situation. According to Bulgarian standard No. RD-02-20-2 for design of buildings and structures in seismic regions it is permitted that construction works, related to the change in the bearing structure of buildings (reconstruction, major upgrade, overhaul and upgrade internal reorganization) or the change in use of the areas and loads in them, only if a survey of the building and its bearing structure is done and a technical passport is prepared and registered in the municipality.