The Netherlands is dealing with two problems. The first is a large housing crisis. Housing is unavailable, unaffordable and lacking in quality and perfomance. There is also a liveability crisis. While the overall liveability score in The Netherlands has been going up in the last two decades, the neighborhood that score the worst have not been able to improve their situation. The most vulnerable group of the population resides in these areas and they are unable to put themselves or their surrounding in a better environment. Post-war neighborhoods consist of a high amount of these low-scoring neighborhood, while at the same time they have a high potential for densfication that would aid in resolving the housing shortage. The question arises how densification can be a catalyst for improving the quality of living in post-war neighborhoods. This thesis investigates the concept of densficitation, its sustainable character and its relationship to improving the quality of living on a spatial and social level. The next chapter looks into the concept of liveability, what it means, what impact it has and what the situation is in The Netherlands. After that, the post-war neighborhood will be researched to gain a better understanding on its problems and potential. The conclusion says that there is definetely a deeply rooted but complex relationship between densification and liveability, one that is far from superficial. By putting clear and strict criteria to the implementation of densification, it is possible to have a positive effect on the quality of living in post-war neighborhoods. These criteria evolve on three levels: 1) mobility, 2) urban blocks, and 3) open space. The thesis proposes a set of criteria and imagines the results of these criteria. By combining the sustainable solution for the housing crisis and measures for the improvement of liveability, it is possible to uplift neighborhoods that deals with social and spatial problems and create a just and healthy urban environment for all.

To achieve a circular economy in South Holland by 2050, the construction and demolition sector must use resources efficiently, close materials loops and work with fewer emissions. Currently recycling building materials is already the approach. Yet, since this costs a lot of energy and results mostly in downcycling, it is not ideal as a long term solution to achieve a durable circular economy. Adding to this, is the space limitation within the continuous growth. The usage of the existing space and infrastructure has to be optimized. This research is answering what is the best strategy to close material loops in South Holland while reusing the existing water infrastructure, amplifying it with integrated (data) networks and improving socio-spatial justice with circular hubs. The research is being executed by analysing the most efficient waterways to use in the area, defining transformation locations according to a data-driven matrix and designing the most efficient circular hub network possible. The waterways will connect circular hubs on 3 scales, a regional processing hub, a city storage & purchase hub and a flexible last mile hub. Transporting materials and goods in between the circular hubs helps in reducing CO2 emission and it can substantiate traffic on the roads. This leads to less busy highways, safer city centres and efficient use of transport. All the logistic flows and used-material flows come together in the Virtual realm, where all used-material data is accessible and a twin-region is ensuring spatial justice. Therefore the concept of Virtual X Water is the answer to define the transition towards a circular economy in 2050.