The existing building in Postgasse is divided into a part with hotel utilization and a second part with flats in the course of reconstruction. This division is carried out by erection of a double wall at the property boundary as well as by cutting the outer walls (from inside). Thus, the demand of the Antiquities and Monuments Office for a joint-less façade can be met and in case of an earthquake the two building parts can fracture at the predetermined breaking point and act independently.
Apart from the rehabilitation of the building, the roof structure is completely converted as steel framework structure and basements are created below the patios. In particular the 4-storeyed subterranean garage in the middle patio, which is made accessible by a car lift, must be mentioned.
For better access and as structural reinforcement several staircases and lift shafts are built in apart from masonry reinforcements.
The total existing building was modelled based on the survey data in 3D and all new building parts are added to the 3D model. In the attic the old wooden roof structure partly protected as historic monument is to be preserved and further used as furniture. The new steel structure is erected above. Apart from complete 3D modelling some field tests were performed by means of HoloLens in order to detect e.g. a collision between the wooden roof structure to be preserved and the new steel elements at an early stage.