Kalleja, Damian

Diploma Thesis:
2072

Topic:
Analysis of the retrofitted addition of storeys to residential buildings as an approach to inner-city housing densification

Editor:
Damian Kalleja

University Professor Responsible:
Univ.-Prof. Dr.-Ing. Dipl.-Wirt.-Ing. Katharina Kleinschrot

Supervisor:
University Supervisor: Dr.-Ing. Jan Kortmann

Editing Period:
13.11.2025 until 10.04.2026

Abstract: 
This thesis examines the retrofitting of residential buildings with additional storeys as a means of inner-city redensification. The starting point is the growing demand for housing coupled with limited land availability. The aim of the thesis is to analyse the technical, legal and economic framework conditions for adding storeys and their feasibility. To this end, the structural requirements for existing buildings, building regulations and project-specific obstacles are examined and evaluated using a practical project as a case study. The results show that adding storeys is generally technically feasible, but requires project-specific solutions. In economic terms, they are inferior to new builds in terms of construction costs, but can be competitive due to the imputed elimination of land costs. Overall, it becomes clear that feasibility is largely determined by the interplay of technical, legal and economic factors, and that a thorough assessment is required in the early stages of the project.