The strategic management of real estate portfolios has become increasingly complex due to global challenges such as climate change, scarcity of raw materials, and changing organizational needs. For large-scale portfolios, such as those of the Ministry of Defense (MvD), these challenges are increased by strict operational requirements, financial constraints, and sustainability objectives. This thesis examines the role of the IFR construction method as a tool to enhance the flexibility and resilience of large-scale real estate portfolios.
The research follows a qualitative, exploratory approach. The central question is: To what extent does the F(lexibility) and R(emountability) in the IFR construction method provide a solution to the challenges of Defense real estate, such as political and economic fluctuations and increasing sustainability requirements? Interviews revealed that “flexibility” is treated as a broad, complex, and often ambiguous concept, lacking a shared definition among advisors, managers, and needs assessors.
Semi-structured interviews with stakeholders within the Rijksvastgoedbedrijf (RVB) and the Ministry of Defense (MvD) form the core of the data collection. It appears that ‘flexibility’ is interpreted much broader and more complex in practice than the original hypothesis suggested, ranging from product-focused physical adaptability to process-oriented standardization and rapid operational reconfiguration. This diversity exposed a clear gap between strategic ambition and practical implementation.
These insights have led to a reorientation of the literature study and the development of a new conceptual framework that maps the different dimensions of flexibility in relation to portfolio management. The framework places emphasis on the physical adaptability of buildings as a prerequisite for strategic flexibility, while showing that organizational capacity and TCO-based management are essential to unlock real value.
This framework is tested in a focus group to validate its applicability and relevance. The results not only provide a better understanding of the role of F and R in Defense real estate, demonstrating how IFR can offer strategic advantages in cost control, adaptive capacity, and material reuse, but also guide how circular building principles can be strategically employed in response to political, economic, and sustainability challenges. The study highlights that long-term benefits, financial resilience, operational response, and reduced material waste, emerge only when physical flexibility is paired with agile organizational structures and clear strategic vision.
The findings underscore the crucial role of circular building in achieving long-term resilience in real estate portfolios. Ultimately, the research shows that the strategic value of remountable construction depends not merely on flexible building design, but on integrated portfolio governance that embeds flexibility at organizational, process, and product levels.
This thesis contributes to the broader concept of circular economy by demonstrating how circularity can transform real estate management into a strategic instrument for resilience and sustainability.

A combined X-ray and scanning tunneling microscopy (STM) instrument is presented that enables the local detection of X-ray absorption on surfaces in a gas environment. To suppress the collection of ion currents generated in the gas phase, coaxially shielded STM tips were used. The conductive outer shield of the coaxial tips can be biased to deflect ions away from the tip core. When tunneling, the X-ray-induced current is separated from the regular, ‘topographic’ tunneling current using a novel high-speed separation scheme. We demonstrate the capabilities of the instrument by measuring the local X-ray-induced current on Au(1 1 1) in 800 mbar Ar.