The aim of this thesis is the preservation of heritage buildings in the 13th district of Vienna. The focus of the analysis is an abandoned property in the cottage district of Hietzing with the address Beckgasse 14. Based on a detailed description of the architectural development of Hietzing and the Hietzinger Cottage district, the history of Beckgasse 14 was reconstructed. Starting from urban analysis, the scale was reduced further and further until finally three neighbouring buildings were analysed in comparison to Beckgasse 14, and identified as properties sharing the same construction details and architectural design. Due to a new design language introduced in 1922 during an attic expansion, the building now represents a transition between development along Lainzer Straße and the Hietzinger Cottage district. Therefore, this property represents a unique object that should be preserved and possibly even considered to be declared as a monument itself.
After extensive investigation it is found that the contradiction between the zoning plan and the protection zone in terms of the constructible area poses a major problem in dealing with the existing building. In order to develop an economically viable and profitable solution that corresponds to the current zoning plan, an economic analysis is carried out on the basis of various developer calculations. Four possible modification variants – renovation, height increase, expansion and new development – are compared. It is discovered that the last two concepts are similar in terms of profitability and dominate the first two variants from an economic perspective. As the expansion variant can also guarantee the preservation of the historical building, several forms of building expansion are tested with the aim that the new volume should not have a negative impact on the immediate surroundings.