Collective Housing in Belgium and the Netherlands: A Comparative Analysis

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 archi‐ tects. 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 con‐ temporary cohousing projects.


Introduction
A decline in the average household size and the ageing of the population have led to a significant increase in the construction of flats by building developers in Belgium. Demolition, renovation, and the construction of housing have also been on the rise in recent years (Statbel, n.d.). The government and social-housing companies generally apply the DBFM (Design, Build, Finance, and Maintain) formula, architects being part of the developer's building team. Whereas architects used to play an independent and leading role, in DBFM their role is subordinate to that of the developer and the investor (PPS et al., 2014). However, there is a field in which architects often take the lead, namely collective housing (CH). Initiatives were taken in the 1980s already, but since 2009 CH has been directed and supported by the team of the Flemish Government Architect, an adviser to the Flemish Government who supports public clients in the design and realization of buildings, public spaces, landscape, and infrastructure (De Bruyn & Maillet, 2014;Swinnen et al., 2012). In this article we focus on Flanders, the Flemish speaking part of Belgium, since we aim to compare Dutch-language terms and influences. However, when taking a historical perspective, we focus on Belgium since the federalization of the country is quite recent.
CH has been a reality for longer in the Netherlands, but here too the phenomenon is on the rise. A housing crisis, in regard to quantity but also affordability, has put CH on the agenda. Citizens organized in various groups are showing an interest in collective forms of living. Local, regional, and national governments are developing various programs to facilitate these initiatives.
Although CH is topical in both Belgium and the Netherlands, the drivers and mechanisms differ. We will therefore explain the historical and political context, cases, and the role of architects in these projects. In terms of methodology, we will make a comparative analysis of the discourses of policy documents and other publications on CH in both countries, complemented by interviews with relevant stakeholders. First, we address the terminology used to describe CH and each country's housing policy. Second, we present and compare two widely published cases in both countries, illustrating various types of CH and the active role of the architect. The cases combine characteristics, such as pioneering examples and recent ones, new constructions, and reuse projects. The thematic mapping of Lang et al. (2018) will be used to frame the comparison.

Context: Housing Policies
To understand the contexts in which CH emerged in both countries, we will briefly introduce their housing policies. Their diverging housing history has influenced current motivations and initiatives for new forms of housing.

CH in a Tradition of Homeownership in Belgium
Belgium has a tradition of homeownership. In the late 19th century already, with the "Loi sur les habitations ouvrières" (Working-class housing act; August 9, 1889), the construction of a personal home was encouraged through low-interest credits (De Meulder et al., 1999, pp. 82-83). But after World War II especially, the influential Christian Democrats in government created a favorable political climate for the massive spread of private home-building by providing substantial subsidies and facilitating mortgages. They argued for detached single-family homes in the countryside, their electoral territory. The highly influential De Taeye Act (May 29, 1948)-named after its proposer, Christian Democrat minister Alfred De Taeye-granted premiums to individual home builders as well as a state guarantee for mortgage loans equal to the full price of their home. As a result, Belgium, and especially Flanders, saw an early increase in homeownership: Today 71.6% of inhabitants in Flanders are private homeowners, mostly in detached housing (Heylen & Vanderstraeten, 2019, p. 37). The Social Democrats, on the other hand, promoted high-rise buildings and large housing complexes in urban areas. On April 15, 1949, a second housing act-the Brunfaut Act, named after the socialist member of parliament Fernand Brunfaut-made provisions not only for the regular annual financing of the construction of housing clusters by semi-governmental and recognized social-housing associations, but also for street layout, including paving, public utilities such as drainage, and open-space planning of grouped houses and flats. That act was an instrument by which to promote social housing. By comparison with the Netherlands, however, social housing remained a rather marginal part of the housing stock, ranging from 2.9% in 1957 to a peak of 30.5% in 1972 and 7.3% today (Cools, 2004, p. 170;Heylen & Vanderstraeten, 2019, p. 37).
Although Belgian inhabitants have a high residential satisfaction rate of 91% (Winters et al., 2013, p. 22), urbanists and architects saw the downside of the housing pattern. Already in 1968, Renaat Braem (1968 criticized the lack of urban planning and the disorderly landscape in his pamphlet Het lelijkste land ter wereld ("The ugliest country in the world"). With the 1997 "Spatial Structure Plan for Flanders," Louis Albrechts (1999) and Charles Vermeersch tried to counter the lack of a strong planning policy and promoted "devolved bundling" to counter the urban sprawl. In 2009 the Flemish Government Architect, at the time Peter Swinnen, began to pay close attention to collective living as a strategy for densification and a means to counter fragmentation. He argued that dispersed urbanization caused several problems, including congestion, destruction of open spaces, loss of coherence in natural environments, inefficient infrastructure, a huge number of utility lines, etc. Swinnen's successor, Leo Van Broeck, reached the general public by using slogans such as "Building detached houses today is criminal" (Piryns & Van Humbeeck, 2017). The current Flemish Government Architect, Erik Wieërs, is pursuing the same track. In an interview he explained that "we should no longer want to have detached houses" (Sels, 2020). In this context, it is significant that his architecture office, Collectief Noord, designed a widely published CH project in Antwerp that we will discuss further.
Outside the world of architecture, in 2000 already a voluntary organization in Flanders called Samenhuizen ("Living together") gathered people interested in collective living. Inspired by cohousing projects in Denmark, they were drawn to a formula that offered, on the one hand, sufficient privacy and, on the other, life in a vibrant community with shared spaces and activities (R. Kums, personal communication, July 12, 2021). In 2009 Samenhuizen received subsidies to conduct a survey on the state of communal living in Belgium (Jonckheere et al., 2010) and the following year it successfully applied for structural subsidies as a sociocultural movement. Since 2011, the association has become professionalized, working with a small team of part-time employees to promote communal living and support candidates. They began to receive subsidies at the time when CH was being promoted by the Flemish Government Architect, marking the contemporary trend of CH in Belgium.
Although the Flemish Government Architect influences the public debate, gives impulses by means of projects and competitions, and advises public-sector clients, his recommendations do not have the force of law, and various regulations hinder the efficient development of CH. On February 2, 2017, however, the Housing Committee of the Flemish Parliament approved a draft decree encouraging experimental forms of housing (Vlaams Parlement, 2017). This six-year pilot project is extendable by four. During this time, projects are evaluated and, in the event of a positive assessment, regulations are adapted within the project period. As such, the government gave the impetus to develop a legal framework for alternative forms of housing that, however, is still in its infancy. In general, and despite these efforts, the procedure remains complicated and most Belgians remain skeptical due to their attachment to their own home and their desire for privacy and autonomy (Bervoets & Heynen, 2013). Moreover, they consider their home as a valuable form of pension saving that guarantees freedom, stability, and security (De Decker, 2013).

A Tradition of Collectivity in Social Housing in the Netherlands
The neighboring Netherlands has a different housing culture, characterized by social housing and national planning policies. An explicit housing policy was made possible from 1901 with the Woningwet (Housing act). It aimed to put an end to unsanitary housing conditions and to promote the construction of good housing. This legal framework provided municipalities with new instruments to deal with the housing need. It encouraged the formation of housing corporations and cooperatives that would build social-housing settlements. It also embedded these initiatives within an urban-planning framework, compelling municipalities to provide urban plans for city expansion and for the existing city (Heynen, 2010, p. 162;Stieber, 1998, p. 73). During postwar reconstruction, the national government drafted a centrally managed plan distributing the number of houses, the materials, and construction workers across the country. In the 1950s and 1960s, municipal housing companies and many housing associations developed social housing, financed by the state and strictly regulated by detailed standards (Lans & Pflug, 2016, p. 52). The three main political movements in the Netherlands also took measures to stimulate homeownership, each from a different angle. The Liberals did so on the basis of equal opportunities in property formation, the Social Democrats on the basis of their vision for the emancipation of workers, and the Christian Democrats on the basis of value for family life. Homeownership in the Netherlands grew from 28% in 1947 to 58% in 2019, but it still lags behind other European countries. Different from Belgium, private com-missioning has failed to flourish in the Netherlands and only accounts for 15% of privately owned homes (Boelhouwer & Schiffer, 2019, pp. 3, 14, 20).
Dissatisfaction with the repetitive housing of the postwar period combined with growing prosperity generated initiatives in the late 1960s that aimed for innovation and more architectural quality in the living environment. In the 1968 national program "Experimental Housing," projects that developed new housing concepts emphasizing participation, among other aspects, were subsidized. In many new areas and urbanrenewal projects, residents became actively and formally involved in neighborhood development (De Vletter, 2014, p. 47). Although a variety of woongroepen (residential collectives) emerged in the 1970s, it was not until the 1984 memorandum "Wonen in Groepsverband" (Living in a group) that government policies responded to this need. Typical of the Dutch context, the housing corporations were key actors in the CH projects, which was problematic because the term "communal space" did not fit their regulations. In the 1980s, legal, financial, and organizational models were developed concerning the relation between residents, association, and housing corporation, for example with regard to participation, maintenance, and management, as well as architect and tenant selection (Krabbe & Vlug, 1986, pp. 9-14).
More recently, a government report again noted increased interest in living with like-minded people as one of the main sociocultural trends, including communities for specific ethnic groups, the elderly, and collective private commissioning (CPO). The report calls for facilitating the empowerment of citizens and communities at local, regional, and national level (VROM-raad, 2009, pp. 41-51, 114). Indeed, several programs supporting housing initiatives have been launched that contain elements of CH. However, in many of the programs that provide organizational guidelines or financial support, CH is not a primary objective. Most provinces offer subsidies for CPO process management. Innovative forms of elderly housing are also supported by the national grant program "Wonen en Zorg" (Living and care) and stimulated in the 2018 competition Who Cares organized by the Dutch Chief Government Architect of the time, Floris Alkemade. These may involve cohousing, but not necessarily. In recent years, a new form of housing association or woongenootschap has revived. In this type of housing association, residents join the cooperative and have a share in the project, but the cooperative owns the housing complexes. Although a successful model in some Dutch cities, in others, like Rotterdam, negotiations with the municipality about available building land have stalled (Van den Ende, 2021). As already reported in the 1970s and 1980s, land allocation by the municipality is an important condition and therefore a means of power for the institutions (Krabbe & Vlug, 1986, pp. 11-12). In short, the strong Dutch tradition of social housing can be seen as an obstacle for new CH initiatives to break free from the organized rigidity of its main stakeholders.

Cohousing Terminology and Criteria
In the Dutch-speaking Netherlands and Belgian Flanders, diverse cohousing models exist and various terms serve to indicate housing concepts involving residents sharing living space(s) and a set of interests, values, and intentions. However, the introduction of Centraal Wonen (Central living) marked the start of 20th-century CH in the Netherlands. Centraal Wonen, which refers to living around central facilities, was initiated in 1969 by Lies van den Donk-van Doorenmaal, who pursued collective living as a way to free women from the burden of housekeeping and motherhood. She invited designers to come up with an efficient housing model where housework would become a more cooperative, centralized effort. After her call for action, a growing group of like-minded people developed the concept further in collective workshop weekends (Fromm & de Jong, 2020, pp. 17-20). In 1978 the national association Centraal Wonen defined the term as: "A way of living where residents-at least three adults-choose each other on the basis of equal rights and share a number of residential facilities" (Krabbe & Vlug, 1986, pp. 7-8). "Central living" is an umbrella term for various forms of housing whose main characteristic is the sharing of common spaces combined with the independent living of each household (Krabbe & Vlug, 1986, pp. 7-8). The projects realized under that association were called Centraal Wonen projects. In 2017 the name evolved to Gemeenschappelijk Wonen (Communal living) to include "all forms of communal living where people choose each other, are open to everyone, and bear joint responsibility: central living, housing groups, live/work communities, eco-projects, etc." (Bakker, 2019, p. 2). In the first 10 years, 36 Centraal Wonen projects were developed in the Netherlands (Krabbe & Vlug, 1986, p. 34). The number has now grown to more than 70. Most are still flourishing today (Krabbendam, personal communication, July 12, 2021).
In Flanders, the Dutch term Centraal Wonen was also employed initially, for example by Samenhuizen, but in 2009 it was replaced by the English term cohousing and the Dutch term co-wonen (co-living). Both housing forms have central units, but in cohousing projects more facilities are shared, such as a kitchen and/or meeting room, which encourages social interaction among inhabitants. Besides cohousing, the terms woningdelen or huisdelen (home or house sharing; to the right in the scheme in Figure 1) are also used, indicating a housing form where different households live "under the same roof" and share (parts of) the household.
Architects mostly use the umbrella term "collective housing." The Flanders Architecture Institute took the lead in defining CH as a mission for architects with the publication Wonen in Meervoud (Living in plurality) in 2009. The book focused on CH that was "architectureworthy." This involved three criteria. First, each individual residential unit of a CH project needed to have the same qualities as an individual single-family home in terms of architecture, comfort, character, cost, and sustainability. Second, building in a group had to provide added value to all homes in terms of location, facilities, etc. Third, there had to be an added value for the community, the neighborhood, and even the city in terms of ecological and other benefits, such as car reduction, residential densification, the reuse of valuable heritage, etc. (Van Herck & De Meulder, 2009, p. 5).
An important milestone was the launch of the pilot project Nieuwe vormen van collectiviteit (New forms of collectivity; Declerck et al., 2013) initiated by the Team Flemish Government Architect. Consortia of architects, project developers, and construction firms were invited to experiment with other housing forms. CH was explicitly mentioned as an important task for architects and other actors involved in housing. Flemish cities too, more particularly their autonomous municipal companies, supported cohousing and developed their own definition. The city of Ghent, for example, defined cohousing as: A housing concept involving a group of people building or renovating a number of private housing units together. The housing units have common facilities. This process pays sufficient attention to the environment and the community feeling. In some cases, it is possible to participate as a tenant in a cohousing project. (Stad Gent, n.d.) This definition stresses collaboration by a group of residents developing and building their homes. In sum, the Netherlands took the lead in CH by introducing the term Centraal Wonen as early as 1969. The projects realized by its associations were called Centraal Wonen projects. A decade later, the term also became known in Belgium but was never widely accepted. The Flemish organization Samenhuizen used the term co-wonen, but ultimately "cohousing" and "collective housing" became the most common terms in Flanders. In the Netherlands, that honor goes to gemeenschappelijk wonen (communal living) as a container term. The Flemish terms refer more to the material dwelling while the Dutch word emphasizes the act of living together.
To classify CH in the Netherlands and Belgium, there is a useful scheme by organization sociologist Peter Camp (2018). He defines four main typologies, all variants of Utopia, organized according to two criteria: sharing facilities (horizontal axis) and sharing activities (vertical axis; Figure 2). YOUtopia stands for few shared facilities and activities, with a focus on neighborhood networks. Cohousing as defined by Samenhuizen fits here. MEtopia is typified by few shared facilities but many joint activities, which is the case in care communities (e.g., assisted housing for the elderly, multigenerational houses). The two typologies with many shared facilities, and thus architectural spaces, are OURtopia and ECOtopia. OURtopia focuses on quality and cohesion in "our" neighborhood or complex. These groups cooperate in the building, renovating, and maintening process, one that often leads to specific architectural projects. In ECOtopia, residents share both many facilities and activities. They are pursuing a better world in certain aspects, as can be seen, for instance, in ecovillages and thematic residential groups. Distinguishing the typologies provides insight into the differences in motivation underlying collective living. The abovementioned Centraal Wonen, for example, can be categorized as ECOtopia, striving for a more social living environment. The emergence in Belgium of Community Land Trustswhere the land is shared by the corporation and members only buy (or rent) the dwelling-can also be included here, as affordability is their main concern. Cohousing as defined by the city of Ghent fits OURtopia, with a focus on the collective development process. Studying the role of architecture in CH, this article focuses on the typologies with shared facilities and building process, indicated as OURtopia and ECOtopia. In architectural discourses, the emphasis is indeed on these projects, which are usually referred to as "collective housing.''

Case Studies
To illustrate the active role of architects in these types of projects and to discuss how the discipline of architecture can contribute to housing as a social endeavor, we shed light on four iconic, widely published CH projects in which architects played a key role as either the initiating, driving, or visionary party. For each country we selected a pioneering older project characteristic of the early days of CH and a more recent one that now serves as an example. Second, we chose a striking greenfield development and an outstanding conversion project. The study by Lang et al. (2018) on "Collaborative Housing" serves as a basis for comparison. The extensive overview of variations in thematic areas revealed in this study is used for the comparative analysis in this article.

Pioneering Refurbishment Project
The Herring Smoking Factory was a pioneering project in Belgium and in 2010 was called the best example of a conversion of a valuable old building (Jonckheere et al., 2010, p. 49). Already in 1984, five households had their eyes on the factory, initially built in 1893 and designed in a neo-traditional style by architect Henri Thielen. At the time it occupied two parcels of land: 750 m² on Kronenburgstraat (18 m facade) and 750 m² on Scheldestraat, for the house of the factory director, a garden, and warehouses (Figures 3 and 4). The families wanted to start a cohousing project, with each family having its own house alongside a communal garden   and other common spaces. The buildings could be protected as a monument of industrial archaeology, entitling the families to grants for the renovation of the protected parts. In January 1986 the sale was concluded, but it took five years to obtain the building permit and the heritage grants.
The fact that one of the candidate inhabitants was an architect (Peter Vermeulen) was important in selecting the site, evaluating the site's potential, and moving forward in the legal and organizational process. Later, Archi-3 was invited to monitor the works to ensure the independence of the architect. In 1993 the conversion of the Herring Smoking Factory was complete. The project encompasses five spacious private houses with a private terrace each, three apartments, and two offices. Two gardens, the garden house, hen house, laundry, and bicycle shed are communal, as are two venues, each equipped with a kitchen. These two venues are used for meetings, parties, and exhibitions by the group itself as well as by friends and neighbors. Once a month, a meeting is organized to discuss practical issues, including chores. Their motto is: "Doing together what we can, so as to have more free time for yourself and for others." The project was awarded the Flemish Monument prize in 1993. It drew a lot of attention on study days and at symposia on CH and on industrial heritage because it was a pioneering project in both cohousing and the reuse of industrial buildings. It is an early example of a conversion project. Later, other buildings such as schools, castles, printing factories, and farms were also adapted to CH projects. The original cohousing inhabitants still live there, but are working on a new, bigger CH project (the conversion of an industrial laundry), where they will be able to grow old with new families (Vermeulen, 2021).

Pavilions as Infill Project
Another widely published CH project in Flanders was carried out by the architectural office Collectief Noord ( Figure 5). This project was commissioned in 2011 by AG Vespa, the project developer of the city of Antwerp, and was realized on the irregular, elongated site of a former printing company. Two entrances provide access to the parcel, one of which is only for pedestrians who can cross the block from one street to the other. For the architects, it was a challenge to open up the heart of the enclosed block to create an oasis of calm, as imposed by the city, on the one hand, and to carry out a densifying residential program of living and working, on the other. Collectief Noord designed three pavilions/houses and its own architectural office. One house is situated above the gateway. The combination of red-tinted brick, concrete elements, and claustra blocks refers both to the surrounding informal garden walls and rear structures, and to a formal, urban architecture. A lot of care went into the outdoor spaces. Each house has an individual rooftop terrace where inhabitants can have dinner in peace, while the collective garden is designed as a real communal space that the inhabitants cannot easily appropriate because the living spaces are on the first floor while the more private spaces (bathroom and bedrooms) are on the ground floor. As such, the communal garden remains communal. No collective activities are planned, but pop-up initiatives like barbecues can always take place. The city sold the units. Architect Erik Wieërs bought one for his family and one for his architectural office, Collectief Noord. The project was acclaimed in many architectural publications as a fine example of a high-quality new-build CH project and green (semi-)public space in a densely populated working-class neighborhood that is now more an "arrival area" home to many nationalities.

Iconic CH Project
The first Centraal Wonen project was realized in 1977 in Hilversum. It is known by the name "Wandelmeent" or "Hilversumse Meent," referring to the address in the neighbourhood De Meenten. It was designed by architects Leo de Jonge and Pieter Weeda. In part due to its striking architectural design with arched roofs, organic urban setting, and brightly colored facade paintwork, this project has iconic value for Centraal Wonen as a movement. To connect the complex to the context, two public streets cross the housing blocks. The complex comprises 50 units ranging from two-to five-room dwellings, providing a diversity of residents that reflect society (Krabbe & Vlug, 1986, p. 36). A distinctive feature for most Centraal Wonen projects is the organization of collectivity on two levels-the overall project and the cluster. At the cluster level, individual units share a kitchen, laundry, and storage (Figure 6b). At the project level, all clusters share facilities such as a café, workshop, sauna, guest room, etc. (Figure 6c). The joint activities differ per cluster, as listed in 1978, from daily lunch and dinner and the shared use of backyards to weekly dinner only (Fromm & de Jong, 2020, p. 76). The irregular composition means that the many niches serve as transition areas inviting collective activities such as picnics and casual exchanges. The organizational process originated from a core group of residents. In 1972 they formed a non-profit foundation as a legal structure allowing cooperation with institutions. They found an architect who was open to participation and willing to work without payment until the site and funding were there. A site on the outskirts of the city was available and housing corporation Gooi en Omstreken agreed to act as the project developer and owner. As in many collective projects in the Netherlands, housing institutions were initially skeptical as no one knew whether the trend would last nor whether such a specifically built form, non-compliant with housing regulations, would be feasible in the long term. The Hilversum group was trusted because it was characterized by "idealism and sobriety" (Fromm & de Jong, 2020, pp. 38-40). Although the residents are tenants, they select the new residents. Candidate residents can register for selection if they are eligible for social housing and are selected by the clusters on the basis of household composition, housing requirements, and mutual expectations. After 40 years, new challenges have arisen like an ageing population and the energy transition, but the Wandelmeent is still a vibrant community.

Dwellings in an Obsolete School Building
A former school building in Rotterdam, typical of the early 20th century, consisted of two floors with three classrooms on either side of the central entrance and a long corridor at the back. The building lies in an enclosed courtyard surrounded by perimeter housing blocks, accessible by a narrow entrance from the street. The vacant school building was owned by the municipality, and the Woonbron housing corporation held the "right of superficies." In 2003 an agency named Urbannerdam, which advises on urban-renewal projects, took the initiative, with Hulshof Architects, to convert the school into nine apartments. The agency then started to recruit candidate residents to form a buyers' association and provide further guidance. The group of residents collaborated as a client in a CPO. The collective work of transforming the school and the individual finishing of the nine residences were completed in 2009. The individual homes range in size from 85 to 210 m 2 as either ground-floor units with a terrace or upstairs flats with a roof terrace (Figure 7). The communal facilities consist of a spacious garden on the former school playground with bicycle storage (Zuijlen, 2013). Collective activities are organized for festive events but also for maintenance, such as "gardening weekends." This school conversion is not so much famous as an individual project but represents a broader trend in the Netherlands, that of transforming outdated buildings such as offices, shops, and industrial buildings into homes. The number of housing transformations is increasing and accounted for 13% of the total addition to the housing stock in 2019 (Goedhuys & van der Wal, 2020, p. 9). The project is also illustrative of the CPO trend, which the government sees as a model that ensures future residents control their future home, with the collective process guaranteeing social cohesion among residents (RVO, 2014). The role of the architect in CPO projects is to realise and integrate individual wishes into a joint design, making the social and organisational aspect of the profession even more important. Five architects live in the nine flats, two of whom worked at the architectural firm involved in the conversion (I. Dijkstra, personal communication, July 21, 2021).

Comparison
To compare the cases, we use a thematic mapping and assessment covering 195 peer-reviewed journal articles on CH (called "collaborative housing" in their article), conducted by Lang et al. (2018). They distinguish five thematic areas: sociodemographic, collaboration, motivation, effects, and context. Since we have already discussed the (historical and policy) context, we will focus on the other categories. These, in turn, are divided into subcategories. In sociodemographic terms, we can investigate the social class of the inhabitants and the demographics (e.g., young people, seniors). The topic of collaboration is divided into governance and the "continuum between 'individuality' and 'collective' " (explained below). Regarding the motivations of CH residents, we focus on the two main motivations we observed in OURtopia projects, namely the importance of affordability and the desire to create commons. Finally, we choose to dwell upon the architectural design, a topic that Lang et al. (2018) classify under the effects, since we want to pay attention to the role of the architect in CH projects, as related to the thematic issue this article is a part of.

Sociodemographic
Most inhabitants of the discussed projects belong to the middle class. They often have a background in culture and/or architecture. The Dutch Wandelmeent project is different as all residents are tenants from diverse backgrounds and the complex is owned by a housing corporation. However, in the Dutch context, social (subsidized) rental housing is available to a large proportion of the population, including middle-class groups. In Belgium, CH is mainly the domain of the middle class, with enough cultural capital to deal with regulations and other obstacles to the realization of the project, but also sufficient money and time to discuss the desired outcome. In three of the four projects, the architects live in these projects. This is not so surprising since a background in architecture is important, sometimes even necessary, to go through the whole legal, management, and construction process. The role of the architect is essential to each project, acting as they do as adviser, project manager, monument guardian, etc. In heritage projects, the architect is crucial for all practical matters. However, the inhabitants often hire a second architect to complete the process so that a certain neutrality is guaranteed (Architectuurwijzer, 2021). In terms of scale, Wandelmeent is by far the largest project with 50 units. That size is rather rare in Belgium. In terms of age, in all the projects it is predominantly young households (with or without children) that joined the project, resulting in an ageing population in the older cases, the Herring Smoking Factory and Wandelmeent. However, CH initiatives for seniors have recently been getting more attention.

Governance
In the Antwerp Herring Smoking Factory, the residents' group is completely self-organized, as they initiated, planned, managed, and governed the project. However, here too we have to stress the crucial role played by the architect. This project illustrates the governance structure of most CH projects in Belgium, at least in the OURtopia and ECOtopia categories.
In the Flemish project of Collectief Noord and the Dutch school conversion Omscholing, the municipality was involved. AG Vespa acted as developer for the city of Antwerp and the municipality of Rotterdam was the owner of the former school building and the plot. In Belgium it is only in the last decade that cities have initiated and supervised CH. In 2011 SoGent (n.d.) was the first government agency to do so. In the Netherlands this ties in with an existing tradition, in which governments are important stakeholders through their ownership of land. In both cases, the architects, Collectief Noord and Hulshof Architects, were involved from an early stage and their role was essential in evoking and visualizing the possibilities of the site and project.
In the Centraal Wonen Wandelmeent project, the organizational process originated from a core group of residents who then contacted the housing corporation Gooi en Omstreken, which acted as project developer and owner. Although the inhabitants were tenants, they chose an architect beforehand and were the driving force behind the project. Also, management of the project was and still is in the hands of a residents' association, which can be regarded as a far-reaching form of self-governance under tenant conditions. This kind of process is less evident in Belgium, where renting occupies a smaller percentage and is often more a formula for the lower classes.

Continuum Between "Individual" and "Collective''
As Lang et al. (2018, p. 10) explain, "this theme represents a continuum between collaborative housing from the perspective of the individual, on one end, towards collaborative housing from the perspective of a "collective" phenomenon, on the other end." In all projects there is a tension between, on the one hand, the importance of "privacy"/autonomy and, on the other hand, "solidarity, social interaction, and sharing." In almost all the projects under discussion, each housing unit deliberately has a private outdoor space (terrace or garden) because it is important to preserve the autonomy of each household. In Wandelmeent, however, several clusters share their backyards. Belgian architects are certainly aware of the importance Belgians attach to autonomy and individuality. Most Belgian cohousing projects have individual terraces or gardens, besides a communal garden or courtyard. In the Netherlands, there are more examples of the sharing of all outdoor space, sometimes providing "threshold" areas as an unfenced intermediary between the collective and private.
The degree to which the communal gardens and other facilities invite interaction and appropriation differs in the projects. In the Dutch cases and in the Herring Smoking Factory, the communal spaces are designed to facilitate and even encourage communal activities, such as joint dinners or meetings. They are sometimes even open to people from outside the project. In the Collectief Noord project, the architects were mainly concerned about the fact that inhabitants would use and appropriate the communal garden too much. They therefore designed barriers between the living spaces of the homes and the garden. They did so by placing the living spaces on the first floor and by providing more private rooms at ground level (even a little deepened). This is in line with the greater importance Belgians attach to autonomy and privacy. This difference is also reflected in the fact that Dutch homes are generally far more open to public space and their windows are considerably less screened (Cieraad, 1997).

Motivations
The motivations for CH in the discussed cases range from inhabitants seeking a different, more social way of living to those focusing on the importance of having a good, affordable home in a high-quality, childfriendly environment. The two early cases from both countries clearly belong to the former category, since living together and sharing facilities and activities (cooking and eating together), even with the broader society, are central motivations and pillars in their community. The ideals of feminist emancipation underlying the Centraal Wonen projects in the Netherlands clearly illustrate this idealistic motivation. Also, the origins of Samenhuizen in Belgium go back to a desire to organize housing differently. In the more recent projects Collectief Noord and Omscholing, the focus is rather on the latter: having a quality home in a dense urban neighborhood. In these projects, inhabitants mention how communal activities have an informal character and arise spontaneously. In the two early projects, the creation of commons, defined by Lang et al. (2018, p. 10) as a "democratic and non-hierarchical organization of housing beyond state and market, which addresses the needs of all its residents" is more specifically mentioned and formalized. These projects explicitly stress sharing activities, borrowing each other's materials, helping each other. The Herring Smoking Factory even explicitly emphasizes the fact that non-inhabitants can also make use of their facilities.

Architectural Design
In CH projects involving the conversion of existing buildings, sustainability is an important motivator, especially the fact that these buildings get a second life, retaining embodied energy, urban structures, and identity. As they are often situated in valuable locations or have precious characteristics, they certainly contribute to the living quality of the inhabitants. Lang et al. (2018, p. 14) point out that in some cases collaborative design practices emerge and that CH provides opportunities for collective and individual learning by residents. In most cases, the residents are indeed involved and join discussions about how to renovate and/or design their future spaces. Only in the Belgian project of Collectief Noord did the architects (one of whom later became an inhabitant) clearly keep control of the design process of the buildings, which is rather unusual. Also in De Omscholing, two architects of the involved architectural firm were future residents of the project. In most projects, the architects have a guiding role and resident participation is part of the design process. In all cases, the result is considered to be of high quality, to the great satisfaction of the residents, and leads to great appreciation within the world of architecture, seeing their inclusion in architectural publications (e.g., Architectuurwijzer, 2021).

Conclusion
Comparing the different national contexts, the various terms in the field of CH, and the case studies, it becomes clear that the term "collective" can refer to different aspects of "housing." The issue for residents in former and future CH projects is: What do we want to share and why? In this article we have found different aspects that may apply separately or in combination, like collective ownership and equal rights (legal); collective building process and participation (process); collective maintenance, agreements, association (organization); collective events, connection, daily routine (social); and collective facilities (economic). But, depending on the various motivations for living collectively, as also distinguished by Camp (2018) and Lang et al. (2018), different aspects play a role.
The comparative analysis between Belgium and the Netherlands demonstrates how CH is intensively discussed in both countries, although their housing traditions and policies differ. In Flanders, CH is promoted by the Flemish Government Architect and the subsidized voluntary association Samenhuizen. The most commonly used terms are "cohousing," co-wonen and "collective housing." However, many legal and technical issues make it complicated. In the Netherlands the government mainly has a facilitating role. In both countries, candidate residents are often the self-organizing initiators. In the past decade, cities have also initiated CH projects in Belgium. The Dutch Government supports CH initiatives but is usually not the initiator. In both countries, economic arguments are a motivation to join a CH project, offering more facilities and conveniences than one could afford individually. Although the scale of the projects generally differs, with more units in the Netherlands (50 and 9 in the Dutch cases) and smaller complexes in Belgium (9 and 4 units in the Belgian cases), both countries show a variety in the continuum of sharing few to many facilities. In the older cases, the idealist notions of collectivity and forming a community seem to be more important than in the later cases.
The main difference between the two countries is undoubtedly tied to the different housing needs and aspirations and can be related to the differences in housing culture and the organization of the housing market. In the Dutch tradition, CH is closely linked to cooperation in the building process, even if the legal developer and owner of the property is often a housing corporation. Also, in the current situation with various models combining renting and buying, there is a distinction between legal ownership and organizational and operational control. In Belgium, private ownership by individual residents in cohousing is the norm, and property, influence, and control go hand in hand.
While most Belgians are satisfied with their owneroccupied homes, groups of residents in the Netherlands see CH as a means to achieve a different quality of living. They feel they can do better than the institutions by establishing their own collectives and associations. Although in the Netherlands too homeownership has increased in recent decades and individual dwellings (homeownership or rental) are the norm, the Dutch see CH as a way of having more say in the design of their home and living environment. For the Belgians, by contrast, CH is rather perceived as a reduction of autonomy. Collectivity in organizational aspects is acceptable or even a driver for Dutch co-housers, whereas it is sometimes an obstacle for Belgians. In the continuum from individual to collective as described by Lang et al. (2018, pp. 10-11), the neighboring countries are on different sides of the collaboration spectrum. In the project of Collectief Noord, the architects were very sensitive to the need for autonomy and privacy of the individual household and the importance to keep the communal garden completely communal.
CH projects are prestigious for socially aware and leading architects in Belgium, but most Belgians remain rather suspicious. Pursuing a more sustainable model in urban planning and land use, the Flemish Government Architect has raised awareness about CH among inhabitants. Architects in both countries play a crucial role in developing the CH project, mostly in close cooperation with the residents. They can spatially facilitate the balance between autonomy and social exchange, which is a key aspect for the well-being of residents and which differs in each case. Moreover, architects are able to create added value for residents and for the broader society. The conversion of abandoned industrial and other heritage sites illustrates this, as is the case in the Herring Smoking Factory and the Omscholing school conversion. But as the Collectief Noord project and Wandelmeent demonstrate, new realizations can also create added value for the broader society by providing collective alternatives to more traditional forms of housing, offering infrastructure to the neighborhood, and contributing to both quantitative and qualitative challenges of the housing market.