In this edition of our interview series, we spoke with architect Stefan Krötsch to explore the evolving role of modular construction and the balance between industrial prefabrication and architectural individuality. Drawing on his experience in both practice and academia, he outlines how digitalization and prefabrication are reshaping design and construction processes, while emphasizing the continued importance of architectural quality and contextual thinking. The conversation also touches on the economic viability of modular approaches and considers how artificial intelligence is beginning to transform architectural practice while underscoring the ongoing need for human expertise.
How do we strike a balance between mass production in the factory and the desire of architects and building owners for custom design, so that not every building looks the same?
Stefan Krötsch: If it were merely a matter of outward appearance, the question could be easily answered by applying a unique façade design to otherwise standard building types. Good architecture is not merely a backdrop, but always forms an integrated system of interior and exterior; it is both a standalone structure and an urban building block. This is particularly significant when the setting is not just any environment, but rather a context with historical or local identity. The distinctiveness and sense of belonging within neighborhoods are also shaped by individual architecture. The serial nature of buildings should therefore be limited to construction projects that are ideally suited to it and inherently involve a high degree of repetition.
The situation is quite different when it comes to the prefabrication of building components or modular units. This refers exclusively to an efficient construction process that takes place largely not on-site but in the factory, yet is tailored to the specific location and project. I consider this to be the modern way of building. Thanks to digitalization, automated prefabrication processes can now be implemented without relying on mass-produced, identical parts. Individual planning and automated manufacturing are therefore no longer mutually exclusive.
What is currently the biggest challenge when assembling the finished modules on the construction site—is it the precision of the components or the coordination of the various trades?
S K: Ideally, no different trades are needed to assemble components or prefabricated modules on the construction site—assembly should be handled by a single contractor. The challenge lies in optimizing all structural and component connections, utility line connections, as well as the necessary site safety measures and intermediate steps, for the assembly process. In conventional construction, planning almost always focuses exclusively on the end result. The higher the degree of prefabrication, the more important it is to consider the construction process and its inherent principles from the very beginning. The assembly process is therefore just as much a design and structural parameter as the structural framework, fire protection, or building physics.
In the best-case scenario, the building is weatherproof and protected from the elements immediately after the components are assembled. Only a few additional tasks should then be necessary on the construction site, such as connecting prefabricated pipe runs or covering assembly joints.
Modular construction promises speed and cost-efficiency—but at what volume or project size does the effort involved in industrial prefabrication truly pay off compared to traditional construction methods? What factors come into play?
S K: In principle, regardless of the type of manufacturing, all components necessary for construction must be produced—whether in a factory or on-site. Work in the factory is usually more precise and takes place under optimal conditions. This tends to lower costs, but has nothing to do with the quantity per se. The key difference is whether higher costs arise from transporting large components or building sections, as well as from special construction details for assembling prefabricated elements, or whether the quantity of identical parts influences the costs. This depends entirely on the type of prefabrication: wall, roof, and ceiling elements can be manufactured and transported as individual parts at competitive costs. Room modules, on the other hand, are expensive to transport but allow for higher degrees of prefabrication (including interior finishing) in industrial production, so the quantity is decisive here. Currently, depending on the project, a repetition factor of 50 to 300 identical modular units is required to compete with the prefabrication of building components. This is why we typically see the prefabrication of modular units in hotels, student dormitories, or similar projects.
AI-powered tools are already handling design tasks, optimizing floor plans, and generating variations in seconds. How does this change the architect’s role in modular construction? Will architects even be needed in the future?
S K: Artificial intelligence will likely take over tasks that were previously handled by staff in architectural firms. This will likely result in job losses in building design. However, there will always be a need for someone to select the right one from the many variants generated in seconds. This will certainly overwhelm laypeople in most cases—especially if good architecture is to be selected. Furthermore, I assume that artificial intelligence software developers will not assume liability for the generated results, as an architectural firm does. In this context, it will be essential for architectural firms in the future to retain control over their own data and experience. A smart initiative by the Bavarian Chamber of Architects in this regard is the founding of a cooperative for architectural firms (ARKO).
In the debate over mass-produced buildings, the question does indeed arise as to whether architects are still needed. But this question is very one-sided. Mass production works well in fields where functionality has been thoroughly explored, such as the automotive industry. Building, as well as living, working, and spending time—in other words, living—in and among buildings has many more dimensions. In the Davos Declaration of 2018, European culture ministers vividly described the importance of architecture for culture, coexistence, and ultimately for the preservation of our identity and democracy. This requires a constant discourse on architecture that continually reinvents itself, preserves our heritage, and thoughtfully builds upon it. For this is what Europeans want, as clearly demonstrated by the popularity of cities and villages that succeed in maintaining and continuing a consistently high standard of architectural quality. This is what architects live and work for. I do not see how this creative work could be replaced by systems or software.
Prof. Dipl.-Ing. Stefan Krötsch
Architect
Stefan Krötsch studied architecture at the Technical University of Munich. He has been working as an independent architect since 2005, and since 2020 has been running the architectural firm Klingelhöfer Krötsch Architekten in Munich and Meersburg in partnership with Ruth Klingelhöfer-Krötsch. After serving as an academic advisor in the Department of Timber Construction at the Technical University of Munich under Prof. Hermann Kaufmann and subsequently as an assistant professor at the Technical University of Kaiserslautern, he was appointed to the Chair of Building Construction and Design at the HTWG Konstanz in 2018. Together with Hermann Kaufmann and Stefan Winter, he authored the standard work “Atlas of Multi-Story Timber Construction” in 2017, a revised edition of which was published in 2021.