Collective housing (CH) is undergoing a revival in Belgium. Since 2009, the Flemish Government Architect and his team have been advocating CH, stressing its importance as a task for architects given the demand for affordable housing and the need to reduce the environmental impact of housing. This support for CH has converged with the work of the non-profit citizen organization Samenhuizen (“Living together”) and the ad hoc initiatives taken by individual households and architects. In the Netherlands too, where there is a longer tradition of CH, the phenomenon is once more on the rise because of the housing crisis. As it is a developing topic, the terminology used for CH is also evolving. Drawing on publications on the subject in both Belgium and the Netherlands as well as on interviews with relevant stakeholders, this article sheds light on two widely published cases in both countries (pioneering and current, greenfield and conversion). These cases are compared in regard to thematic areas, based on an extensive literature study on collaborative housing by Lang et al. (2018). In addition to such aspects as the balance between “individuality” and the “collective,” we compare the role played by architects in both countries. Besides similarities, we show that the historical context, and especially the housing policy of each country, has a great influence and that the role of the architect is essential in the development of older and contemporary cohousing projects.

In the first post-war years, New Belgrade denoted a concept of a new city on the left bank of the Sava River, opposite to historical Belgrade. Initially, it was planned as a capital of Yugoslavia, a centre of administration, culture and economy. However, its basic purpose changed in the following years. As elsewhere in post-war Europe, affordable housing was high on the agenda. Therefore, New Belgrade was eventually realized as a city of housing mega-blocks, as an answer to the housing needs. In the period that followed, urban development strategies and policies were changing, thus New Belgrade passed through different levels of transformation. Today, the modern blocks are left to decay, while the urban pattern of New Belgrade is being altered once again, now by market-oriented urban practices. This paper investigates the metamorphosis of New Belgrade, and analyses the housing blocks in order to present their values and to contribute to the preservation issue, but also to highlight their current condition and need to be adapted. Furthermore, it aims to rethink the adaptive capacity of applied prefabricated systems: it investigates if their flexibility and modularity can provide adaptability of the structures to today's requirements. The analysis is conducted through a comparison of two buildings in Block 23: two prefabricated systems - panelised and IMS (Institute for testing of materials) skeleton system, layouts and appearance. Their ability to adapt to the contemporary context and needs is recognized as one of the most important criteria in the analysis on how sustainable the mega-blocks are.

Yugoslavian Modernist Architecture, although part of a larger cultural phenomenon, received hardly any international attention, since there are only a few internationally published studies about it. Nevertheless, Modernist Architecture of the Inter-war Yugoslavia (Kingdom of Yugoslavia), and specially Modernist Architecture of the Post-war Yugoslavia (Socialist Federal Republic of Yugoslavia under the "reign" of Tito), represents the most important architectural heritage of the 20th century in former Yugoslavian countries. Belgrade, as the capital city of both newly founded Yugoslavia(s), experienced an immediate economic, political and cultural expansion after the both wars, as well as a large population increase. The construction of sufficient and appropriate new housing was a major undertaking in both periods (1919-1940 and 1948-1980), however conceived and realized with deeply diverging views. The transition from villas and modest apartment buildings, as main housing typologies in the Inter-war period, to the mass housing of the Post-war period, was not only a result of the different socio-political context of the two Yugoslavia(s), but also the country's industrialization, modernization and technological development. Through the classification of Modernist housing buildings in Belgrade, this paper will investigate on relations between the transformations of the main housing typologies executed under different socio-political contexts on the one side, and development of building technologies, construction systems and materials applied on those buildings on the other side. The paper wants to shed light on the Yugoslavian Modernist Architecture in order to increase the international awareness on its architectural and heritage values. The aim is an integrated re-evaluation of the buildings, presentation of their current condition and potentials for future (re)use with a specific focus on building envelopes and construction.