Public-cooperative policy mechanisms for housing commons

Abstract Cooperative housing is experiencing a resurgence of interest worldwide. As a more democratic and affordable alternative to dominant housing provision, it is often heralded as a blueprint for ‘housing commons’. Despite its long history, however, cooperative housing has rarely gone beyond a ‘niche’ in the housing market. Recent critical housing scholarship is beginning to address this marginalisation and understand how a more widespread development of the sector can be supported. In times and places where cooperative housing has expanded beyond a ‘niche’ solution, the role of the state, through policy making at national, regional and municipal scale, stands out as an important enabling factor. Drawing on ten international cases, this study presents a framework for a rigorous and politically meaningful comparative approach to public-cooperative policy mechanisms for ‘housing commons’. Three key phases in the housing process (production, access and management, and maintenance of the model in time) are identified and discussed through concrete examples of policy areas and mechanisms. The article contributes to scholarship on cooperative housing policy making and ‘housing commons’ and argues for a shift in attention to questions of accessibility over time, and the thorny issue of permanent decommodification.


Introduction
Cooperative housing has been receiving renewed attention as one of the possible responses to the 'return of the Housing Question' (Hodkinson, 2012b) since the 2007-8 mortgage meltdown and global financial crisis. Its focus on decommodification and self-governance have made it the embodiment of an affordable alternative to both market and state housing provision. Despite its long history, however, cooperative housing has rarely gone beyond a 'niche' in the housing market (Saegert & Ben ıtez, 2005), a 'supplementary form of tenure' (Kemeny, 1981) or a degree of 'tokenism' (Harloe, 1988). Hardly an alternative, it would seem, for those other than the 'happy few'. In the times and places where cooperative housing has expanded beyond the margins, however, state support and recognition stand out as key enabling factors. In these contexts, cooperatives have sought to balance their independence with access to external resources and expertise (Mullins, 2018;Mullins & Moore, 2018), developing a relationship with the state that could be characterised as one of 'embedded autonomy' (Ganapati, 2010). Given the resurgence of cooperative ideas and practices as a response to the crisis of dominant housing provision, exploring the nexus between the state and the cooperative sector is key to understanding and developing what could be termed public-cooperative approaches to housing.
The impetus for a better understanding of the public-cooperative nexus is situated in the emergence of cooperative housing in crisis-hit Catalonia, which sets the scene for this study. In the wake of the 2007-8 crisis, grassroots urban movements and non-profit organisations started promoting cooperative housing as an affordable and decommodified housing alternative (Cabr e & Andr es, 2018; Larsen, 2019a;Pointelin, 2016;Scheller & Larsen, 2019). Since 2011, more than 50 initiatives have emerged around cooperative and 'collaborative housing' (Cophab, 2018), thanks in part to the recognition and support from coordinated networks of supporting organisations and municipal policy-making (Mart ı-Costa & Ferreri, 2020). The search for further recognition and growth by the cooperative housing sector in Catalonia has promoted a political and academic investigation into the question of the potential role of the state as an enabler, through the promotion of a favourable legal and policy environment. In this paper, we reflect on an overview study on the legal and policy tools employed in different national, regional and municipal contexts to establish and develop public-cooperative frameworks to produce cooperative housing as an affordable, accessible and (partially) decommodified alternative. The study was commissioned by La Dinamo, a foundation that promotes cooperative housing in Catalonia, and brought together examples of highly diverse public-cooperative housing mechanisms in ten different contexts. 1 It has often been noted that realising comparative analysis of housing sectors presents complex and at times unsolvable issues of translatability and historical exceptionality. On cooperative housing policies, precedents to date include comparative studies of a small number of cases (Ganapati, 2010;Lang & Mullins, 2015), bi-national comparisons (Balmer & Bernet, 2015;Minora et al., 2013), international reviews of academic and cooperative sector literature  and nonacademic publications (Crabtree, Perry, Grimstad, McNeill, & Power, 2019;Moreau & Pittini, 2012). By approaching the public-cooperative nexus as a political issue comprising planning, housing policy and governance, we offer a first attempt at a systematic international comparison of legal and policy mechanisms for promoting cooperative housing as an accessible, affordable and (partially) decommodified housing alternative.
In what follows, we reflect on the theoretical and methodological questions emerging from this commission to discuss the complexities of developing a comparative approach that is both scholarly rigorous and politically meaningful. The paper is organised as follows. The first section lays out the theoretical orientation of the study within the paradigm of 'housing commons' and its operationalisation through public-cooperatives mechanisms. The second section outlines the methodological reasoning behind the definition of cooperative housing and its relevance for cross-case comparisons. The third section explains the framework we deployed to compare publiccooperative housing policies; this is followed, in the fourth section, by a discussion of the three key phases (production, access and management and maintenance of the model) through international examples of policy areas and concrete policy mechanisms. We conclude by discussing potential and limitations of this framework and offer lines for further comparative investigation.

Housing commons and public-cooperative relations
The hyper-commodification and financialisation of housing lie at the root of critical diagnoses of the current global housing problematic (Marcuse & Madden, 2016, p. 80). The removal of restrictions on housing as a commodity, be it through processes of deregulation of land and housing markets or the privatisation of public housing, can be conceptualised as instances of 'new urban enclosure' (Hodkinson, 2012a; see also Aalbers & Christophers, 2014).
The terminology of urban and housing enclosures has been set in theoretical and political contraposition to that of the commons, 'enclosure's antonym' (Linebaugh, 2014, p.142). The dialectical interplay between enclosures and commons (Sevilla-Buitrago, 2015) points to the ways in which capitalist urbanisation is an ongoing and open-ended process that is continuously contested, reinvented and reinforced. The commons, within this dialectical thinking, designates all those examples of constitutive collective social practices based on a community of reference and the selfmanagement of a non-commodified resource (Federici & Caffentzis, 2013;Harvey, 2012), in dynamic relationship to forms of capitalist spatial rationalities. Of relevance to this study, the collective member-based structures of housing cooperatives, which facilitate the combination of political and economic democracy (Clapham & Kintrea, 1992), have long been taken as examples of existing housing commons. In recent years, however, the focus of the debate has shifted from a somewhat narrower study of concrete typologies of decommodified housing tenures, such as community land trusts and mutual housing cooperatives (Bunce, 2016;Thompson, 2015), to understanding multiple and complex processes of production, management, financial and political mechanisms for taking and maintaining housing outside market dynamics (Huron, 2015(Huron, , 2018Joubert and Hodkinson, 2018;Larsen & Lund Hansen, 2015).
Within these mechanisms, a significant element is the role played by state institutions. While as a theoretic-political proposition housing commons identify an alternative beyond the dichotomy between the state and the market, the public and the private, their historical development within capitalism has proven contradictory. The commons under contemporary urban conditions can only really be imperfectly enacted or prefigured 'inagainst-and-beyond' the state and the market (Caffentzis & Federici, 2014;Cumbers, 2015;Holloway, 2010;Wainwright, 2007). Or as Huron (2018, p.155) puts it in her study on limited-equity housing cooperatives in Washington DC, the commons is 'a pragmatic practice to be pursued, within and between and against capitalist practices'. The practical operationalisation of the commons takes on diverse and 'hybrid' organisational and institutional forms. These, moreover, are subject to the twin pressures of commodification or state control, and the competing arguments about private or public benefit, that dominate capitalist political economies.
One of the main theoretical and political challenges, as Federici and Caffentzis (2013) argue, is finding ways of connecting the struggles for the construction of the commons to political struggles over the 'public', commonly understood as the realm of the state. Eluding this challenge denies the 'progressive potential of state-led redistributive strategies' (Bakker, 2008, p. 248). The state, after all, can be instrumental in the 'common-pooling' of resources at a societal level through taxation and spending and interventions over property rights (Vidal, 2019b). Constitutive practices of housing commons intersect with state rationale and functions in realms such as planning regulations and allocation of land and resources, but also, importantly, through the organisation and administration of societal claims and demands through social and housing policy-making. Housing put in common often involves 'layered or nested rights' (Bruun, 2015, p. 162) and 'multiple claimants' (Amin & Howell, 2016) that go beyond a strictly predefined community and a narrow definition of insiders and outsiders. The state can set significant limitations and barriers to self-organisation, but also use its redistributive powers to support initiatives and act as one of the channels for wider social claimsfor instance, by establishing housing affordability criteria -albeit in highly mediated, indirect and contradictory ways. According to Harvey (2012, p. 87), what is required then is a 'double-pronged political attack' that acknowledges the role of the state and forces it to supply a flow of resources that can then be appropriated as commons. On a practical level, without involvement in wider redistributive processes, self-help initiatives are easily constrained to an alternative for the 'happy few' by existing inequalities in access to and ownership of land, property and capital required for their establishment and maintenance.
Appropriating housing as commons through the constitution of cooperatives may therefore require the development of specific mechanisms and forms of relations between the state as a public administration and the housing cooperative. In contraposition to the public-private partnerships characteristic of neoliberal urbanisation, in such public-cooperative arrangements the cooperative can act as a 'non-state public' (Laval & Dardot, 2015) rather than a 'private' counterpart. These relations can be situated within 'public-community-cooperative matrices' (Mir o, 2018, p. 175) or understood as one of the ways in which 'public-common partnerships' (Russell and Milburn, 2018) take shape. Such interplay between state and non-state organisations is seen by Dyer-Witheford (2007) as the potential basis of a 'New Deal' based around the notion of the commons. These relations can take different forms, from closer ties through shared governance structures to looser regulatory or financial links.
Terms such as 'partnership' and 'New Deal', however, overplay the collaborative over the necessarily conflictive and contradictory aspects of such arrangements. The balance between housing cooperatives' embeddedness in the state and autonomy is a precarious one (Ganapati, 2010;. There is no pre-existing 'common good' or 'general interest' to be jointly pursued by state and non-state bodies such as housing co-operatives. Rather, these public-cooperative arrangements emerge from political alignments that are often fraught by antagonistic and contradictory forces, subject to always-looming marketisation pressures and involve a state that ultimately governs through and for capitalist rationales rather than for the commons. As Mullins et al. (2018, p. 3) note, these forms of 'hybridisation' are contested processes, which on occasions can take on 'monstrous' qualities (Blessing, 2012) and elude democratic control (Swyngedouw, 2005). The public-cooperative nexus develops through both collaboration and conflict and ongoing social and political struggles. These processes underpin the specific legal and policy tools, and hybrid reconfiguring of roles and functions, that we identify and discuss below in relation to cooperative housing.

Delimiting the cooperative alternative
Having positioned the theoretical orientation of this study within the broader framework of housing commons and the public-cooperative nexus, in the following we discuss in greater detail the steps taken to delimit the cooperative housing alternative and the methodological issues encountered in developing a comparative international framework.
Comparative housing research is a field characterised by unique local institutional configurations and strong historical path-dependencies (Bengtsson and Ruonavaara, 2011), and often hindered by limited availability of comparative data and different definitions of tenure, affecting even mainstream categories such as social housing (Scanlon et al. 2015). Although cooperativism has a well-established set of principles, it has produced very diverse housing in different contexts (Moreau & Pittini, 2012), which presents a further challenge to the already complex nature of comparative research. Cooperativism in housing has yielded considerably heterogeneous sectors in regard to size, historical trajectory, tenure regimes and institutional and organisational forms. The cooperative label has been attached to a wide variety of housing models, some of which embody commodified or state-provided housing in all but name. 2 Such a broad denomination has blurred the specificity of cooperative housing as a non-state, collectively managed and (partially) decommodified alternative, the criteria most in tune with the housing commons framework guiding our approach.
Consequently, we had to carefully delimit the object of study. We decided to focus on cooperative housing initiatives that met two key conditions. The first is that residents, at least nominally, have control over the collective management and/or ownership of the buildings; and the second, that the individual housing units cannot (at least in the original intention) be bought and sold on the open market. That is, where residents collectively manage and/or own but cannot capitalise upon the (full) exchange value of their homes. These conditions are restrictive enough to capture the non-state, collective and (partially) decommodified specificity of cooperative housing, but also sufficiently broad to include a varied range of housing trajectories. This delimitation encompasses cooperative housing models based on rental tenure and others on cooperative share ownership, models with a large degree of self-management and others that are highly professionalised; models that are very closely aligned with the social and public housing sectors and others that remain largely autonomous from state institutions.
These two conditions were understood as able to encompass housing initiatives and sectors that may not be formally denominated or legally registered as cooperatives in their national contexts. This is the case in Denmark, for example, where both 'private housing cooperatives' (private andelsboligforeninger) and 'common housing' (almene boliger) have shared roots in the country's history of housing cooperativism (Jensen et al., 2013;Larsen & Lund Hansen, 2015). The latter sector includes housing associations collectively owned by tenants, who participate in their governance through a system of 'tenant democracy'. Another example is the housing projects in Germany that form part of the Miethauser Syndicat, which are governed by cooperative principles but are legally registered as a limited liability company (Balmer & Bernet, 2015). Our definition of cooperative housing thus attempts to go beyond formal denominations to capture the substantive character of the housing form considered.
Our commons-oriented focus on the collective and decommodified aspects of cooperative housing differs in important respects from other recent approaches to emerging alternative forms of housing, such as those that mobilise 'collaborative housing' as an international umbrella term (Czischke, 2018;Czischke et al., 2020;Fromm, 2012;Lang, Carriou and Czischke, 2020). The latter term encompasses a variety of housing forms with, 'high degrees of user participation, the establishment of reciprocal relationships, mutual help and solidarity, and different forms of crowd financing and management' (Czischke, 2018, p. 56). This approach focuses on resident participation in housing, but is at times less attentive to the market and property relations in which specific tenures and housing forms are embedded. In particular, definitions of 'collaborative housing' do not necessarily exclude commodified forms of housing, as, for example, owneroccupied cohousing developments (Larsen, 2019b). Given that new enclosures through commodification are the kernel of the contemporary 'housing question', this openness renders this literature a potentially problematic reference point for the study of housing commons. Central to 'collaborative housing' is also 'a significant level of collaboration between (future) residents' and 'external actors and/or stakeholders,' (Czischke et al., 2020). In this framing, 'collaboration' remains a suggestive notion that however says little about the material and power relations that underpin it.
In our study, in contrast, we delimit the cooperative alternative through a nominal resident collective control over the management and/or ownership as a key criterion. This condition provides residents with a power resource that can potentially be leveraged in a more substantial manner than merely 'participating' and 'collaborating' in the housing process. In practice, however, nominal collective management rights and/or ownership are admittedly an insufficient condition for genuine resident empowerment and participation. They, moreover, do not in themselves necessarily ensure the permanent decommodification of housing, nor do they guarantee its openness to wider societal needs beyond those of its members. A concern that is fully shared with the 'collaborative housing' approach regards potential insularity and nepotism in cooperative housing. Sørvoll and Bengtsson (2020), for example, stress that cooperative 'internal solidarity' can produce 'self-sufficient enclaves in relation to the wider society'; whilst Thompson (2020) argues that existing housing cooperatives tend to be mostly 'inward facing' as they are 'designed to work for the benefit of their members alone' (p. 83). In effect, cooperative housing can be held as commons between members, but exclusively vis-a-vis the outside world (Rose, 1994, p. 134). It can also be altogether dissolved as a commons from within by members through its commodification (Vidal, 2019a). To prevent both extremes, cooperatives can become embedded within multi-stakeholder governance structures and/or public regulations.
In the context of intensified urban enclosures, the interconnected issues of permanent decommodification, collective self-governance and accessibility to non-members (as a mechanism to avoid insularity and nepotism) need to inform a critical framework for a comparative approach. As we discuss in the following section, the framework that we propose and apply in this study is not designed to explore the institutional and organisational specificities of different cooperative housing models, but rather the legal and policy tools that promote their accessibility and decommodified character.
A framework for comparing public-cooperative housing policies In designing an approach and research strategy for comparing publiccooperative housing policies, decisions were guided by theoretical considerations, but also by a specific political and practical purpose. The political objective was to win further public support in promoting and sustaining the affordable, accessible and decommodified character of cooperative housing. The practical purpose was to produce knowledge that could be instrumentally employed in lobbying activities towards different public administrations. As a result, the project approached housing with a longterm perspective, so as to be attentive to the insularity and commodification pressures on the cooperative housing stock that can emerge with time and in changing contexts. It then identified the different phases in which the state, its various functions as a regulator, land and property owner, policy-maker and administrator of social demands, became involved and the legal and policy tools employed. The objective was not to achieve a deep understanding of the context and impact of these legal and policy measures, but rather to produce a comprehensive toolkit that could be potentially repurposed, reassembled and readapted in different housing contexts, including the Catalonian one.
A long-term perspective including both housing production and consumption contrasts with the production-oriented focus of much housing research and policy. Our concern was not just the production of cooperative housing, but also the evolution of the cooperative model in time, and the potential for maintaining decommodification. Following Turner (1978) 'housing' is both noun and, more importantly, a verb -the process or activity of housing. As Doling (1997, p. 48) notes, such a processual approach is useful in, 'identifying elements or points in the process at which government may become involved in order to effect policy ends'. Ambrose (1992, p. 173) argues that 'unpacking' the process of provision of housing into its 'constituent states' is an analytical approach that can clarify policy issues. This approach follows the set of stages through which housing units pass and which together conform what he calls the 'housing provision chain ' (1991, p. 92).
Our comparative analytical framework is an adaptation of this processual approach to the particularities of cooperative housing and the role of public authorities thereof. We distinguished three key phases or 'moments' in which public intervention is critical in shaping the concrete outcomes of cooperative housing ventures (Baiges et al. 2019): 1. Production of cooperative housing. Public powers can promote the formation of cooperatives through measures that enable access to land, existing buildings, finance, economic resources and technical support. These factors will determine the overall initial costs of the housing project and thus its initial affordability. They also weigh heavily on the ability to scale up and replicate housing cooperative developments. 2. Access to and management of cooperatives. Public authorities can influence the norms regulating access to cooperative housing to prevent potential insularity and keep the sector open to a diverse public. They can also improve the long-term affordability of cooperative housing by providing subsidies to cover housing costs for low-income residents and to support maintenance, repair and improvement work of the housing stock. This categorisation is not strictly chronological but rather substantive. Although we use the term 'moment' or 'phase', it is important to point out that they are often not separate and clearly defined periods of time, in fact they may even overlap. Each of these phases could also be subdivided into more concrete categories. Our production phase-the creation of new cooperative housing, for example, groups together three stages identified by Ambrose (1991, p. 92): 1. Promotion-the act of initiating the scheme 2. Investment-the input of money to assemble factor inputs. 3. Construction-the actual production of a housing unit. Focussing on the three phases or 'moments', we enacted a political rethinking of what a meaningful comparative approach could entail, structuring our cross-case comparisons in ways that drew attention to the presence of enabling mechanisms within different policy areas (see Table 1).
The empirical basis for the investigation consists of case studies from 10 contexts, commissioned to different housing researchers and practitioners. In the selection of cases the study chose a wide angle to explore a variety of the public-cooperative mechanisms available, rather than following a strict, best practice approach. Therefore, alongside mainstream and wellestablished cooperative housing sectors, the study also included relatively experimental or short-lived programmes which nonetheless present interesting and relevant approaches. This heterogeneity reflects the diverse levels of housing and planning governance, as well as the different degrees of maturity and integration of cooperative housing policy making across different levels of governance. Each case-study author was provided with the aforementioned framework to guide their research and structure their inputs. Data from the 10 case studies was then compared through a threemonth iterative process of analysis which included careful translation between different languages, definitions of tenure, and legal and policy frameworks. Further clarifications were sought and details added to better understand national and regional peculiarities, as well as the position of cooperative housing in relation to the wider housing and planning systems, and to ensure comparability. For each example, we further identified the level of governance and policy making, distinguishing between municipal (M), regional and/or national (combined into the Supra-Municipal -SM-category in Table 1).
Although in the final report each case study included an introductory contextualisation, the reduction of complexity required for any comparative exercise was achieved by sacrificing a comprehensive account of each housing system and its wider context. Our comparative framework privileged the identification of policy areas and mechanisms above in-depth contextual accounts, in order to facilitate international comparison. Understanding how housing policies and other policy instruments operate requires analysing the ways in which they interact with public and private institutions that form the housing system at point of emergence and over Table 1. Public-cooperative housing policy framework.  time Stephens, 2011); however, this was beyond the scope of this comparative study. Our aim was rather to identify and understand key policy areas and mechanisms in order to support local advocacy and policy-making in Catalonia and beyond. 'Context matters', as Peck (2011, p. 791) insists, and, 'the 'objects' of policy transferpolicy ideas, innovations, technologies, and modelsdo not float freely in some unstructured universe.' Rather, the field of policy transfer is, 'saturated by power relations' (ibid) and political agendas. Selective de-contextualisation in policy transfer has been used knowingly as a 'political weapon', 'lesson drawing' being 'a form of advocacy by proxy' (Peck, 2011, p. 778). Yet, whilst Peck critiques the use of this strategy by technocrats and a 'narrow elite of policy makers ' (2011, p. 785), it can also be turned upon its head and appropriated instrumentally by grassroots and right-to-housing organisations for bottom-up policy making.

Between production, accessibility and permanent decommodification
In what follows we discuss in greater detail the three key phases or 'moments' of the framework we propose, outline corresponding policy areas and offer examples of concrete policies to illustrate its significance for understanding cooperative housing as a commons and its relationship to public policy making.

Production
In our cross-case comparison, we identified 5 different policy areas in which public administrations support the production of new housing cooperatives in their cities and regions: access to land and buildings, access to financing, direct and indirect subsidies, and technical support.
Measures facilitating access to land for cooperative housing make up one of the most common policy areas. A key public support mechanism identified is through the sale of public land for new housing cooperative developments, at municipal 3 or national level. 4 In some cases, and particularly urban areas where public land is a scarce resource, the practice of land leasing is implemented to keep land in public ownership and counter longterm privatisation trends. In the German municipality of Leipzig, for example, such leases range between 30 and 99 years (H€ olzl & Bernet, 2020, p. 40). In Holland, where the leasehold model has a long history, most local governments use an unlimited lease model (erfpacht) for developing notfor-profit housing. The growing traction of lease-based mechanisms for accessing land is appearing alongside the introduction of new, hybrid models of governance for decommodified land ownership such as Community Land Trusts (Bunce, 2016;Davis, 2010;Thompson, 2020). The third mechanism identified is inclusionary zoning that incorporates a percentage of cooperative housing units. In Germany, for example, municipalities such as Hamburg reserve 20% of new developments for Baugemeinschaften projects 5 (which includes both cooperatives and foundations) and in Denmark, municipalities can reserve up to 25% of new developments for Almene boliger (common housing). 6 Diverse policies also support the transfer of ownership and/or management over existing buildings to cooperative housing. In the framework of rehabilitation programmes, local governments have promoted the transfer of buildings in need of renovation. This was the case of programmes such as the Affordable Neighborhood Cooperative Program and the Third Party Transfer Program in New York City (Cabr e, 2020). Some rehabilitation and cooperativisation programmes have also allowed for the regularisation of squatted buildings. 7 Another route is through the transfer of management, or ownership, of the public or social housing stock to housing cooperatives. In Holland, for example, the 2015 Housing Act established a framework for social housing associations that supports existing groups of tenants who wish to form a housing cooperative and become collective owners of the buildings in which they live. 8 When such transfers of ownership occur in a wider context of welfare state retrenchment, however, housing co-operatives can become a potentially problematic 'private, self-organized solution to a public problem' (Balmer & Gerber, 2018, p. 378). Mechanisms that, in contrast, enable tenure conversions in the privately-owned housing stock are rights of pre-emption and first-refusal for cooperatives. These were notably key to the establishment of cooperative housing in Denmark after 1976, via the collective acquisition of private rental properties by tenants organised in cooperative associations (Larsen & Lund Hansen, 2008;Vidal, 2019b).
Alongside the physical resources mentioned above in the form of access to land and buildings, cooperatives need financial support to ensure that new built and renovation projects are economically viable. Public support usually takes the form of public lines of credit, in the form of public loans such as in Uruguay and Austria; public guarantees to access private credit in more favourable conditions, as in Denmark and Holland; or direct and indirect subsidies. In some cases, direct subsidies for the cooperative model exist alongside more general subsidies for the affordable and social housing sector, such as in Quebec, where up to 50% of the mortgages can be converted into non-refundable subsidies. 9 Indirect subsidies depend on the type of membership and the non-profit nature of housing cooperatives, which makes them exempt from specific taxation, such as property taxes (e.g., Uruguay and Denmark), and corporate taxes (e.g., Quebec and Austria).
Finally, beyond land and buildings, and access to financing and financial aid, in most cases public authorities played some role in the provision of technical support to cooperatives, ranging from information and training to technical assistance. In countries with advanced and established cooperative housing sectors, support is provided directly by independent professionals whose cost and working are regulated by the public administration: such as the Technical Resource Groups (GRT in French) in Quebec and the Technical Assistance Institutes (IAT in Spanish) in Uruguay. The emphasis on co-design and participation, and the 'hybridisation of knowledge' central to models of collective co-created housing, often 'presents a serious challenge to the current top-down planning cultures' (Tummers, 2016(Tummers, : 2030; technical support can therefore be essential to overcome socio-technical issues and engage with regulations during housing production.

Accessibility (access and management)
As previously discussed, a key critique of community-managed decommodified housing is that in practice it falls short of ideals of housing alternatives by reproducing 'inward facing' and 'secluded enclaves' of housing commoners in the form of cooperative housing members (Stavrides, 2019;Thompson, 2020;Tummers, 2016). Public administrations can play an important role in designing and implementing regulations on cooperative housing to improve accessibility in terms of access and affordability. Two main policy areas stand out in our analysis: criteria and regulations on access to the cooperative housing stock, and subsidies to maintain affordability.
In exchange for public support, public administrations may set eligibility criteria and selection mechanisms for cooperative members and regulate processes of transference of housing units (Minora et al., 2013). Accessibility to low and middle income populations has been pursued by placing income limits and/or quotas for people on social or sheltered housing registers. Income limits include general income ceilings such as in Uruguay or affect only part of the cooperative's housing, so as to guarantee an income mix, such as in Quebec. 10 In cases where percentages of housing units reserved for social or municipal housing waiting lists exist, these range from around 10% for publicly-supported cooperatives in Denmark to 30% in Vienna. Another key dimension subject to public regulations is the inheritability of cooperative housing, ranging from its prohibition in Quebec to its availability for relatives in Italy. Finally, norms over the functioning of waiting lists managed by cooperatives have also been determinant in cases such as Denmark, where regulated and transparent waiting lists in the 'common housing' sector (Almene boliger) contrast with criticisms of nepotism in unregulated private housing cooperatives (privat andelsboligforening) (Bruun, 2015). Overall, external regulations often coexist in a delicate balance with collectively managed housing and individual cooperatives maintain varying degrees of autonomy in the selection of members.
In many cases, the long-term affordability of cooperative projects is supported through public subsidies to cover running costs. The first mechanism to ensure it is through subject subsidies for monthly payments (in the form of rent or fees), which is present in the majority of the examples, and generally by regional and/or central governments. These subsidies allow low-income households to join cooperatives and help residents cope with the occasional financial difficulties they may experience. In the words of the Uruguayan Federation of Mutual-Aid Housing Cooperatives (FUCVAM, in Spanish), these subsidies are essential to ensure the 'right to remain' in housing cooperatives (FUCVAM, 2016). In most cases, the subsidies are based on income; in a few, they are based on the ratio between income and housing expenses. Subsidies may also exist to support building maintenance and renovation, which represent a significant expense for older cooperatives. A long-term policy approach usually incorporates maintenance as essential, such as in Denmark and Quebec. In some cases, cooperative housing may receive more favourable conditions to subsidies for occasional and comprehensive rehabilitation, such as at the municipal level, in the City Council of Montreal. 11

Permanent decommodification (maintenance of the model)
The third phase to support the permanent decommodification of cooperative housing brings the investigation back to the political grounding of this inquiry in a context of permanent crisis triggered by housing commodification. For cooperative housing to be an alternative to the dominant system of housing provision, in Catalonia as elsewhere, there needs to be a longterm view to the mechanisms that enforce the decommodification of the housing projects and of the individual units. Longitudinal studies of cooperative housing sectors across the world, such as in Denmark (see Larsen & Lund Hansen, 2015), Uruguay (Vidal, 2019a; and Puerto Rico (Morales, 2018) have shown that the creation of mechanisms to avoid commodification is paramount to maintain co-operative housing as an accessible and affordable alternative to market housing. Rather than a separate 'moment', the issue of maintenance of the model in time thus runs across both issues of production and of access and management, revealing strengths as well as weaknesses of different models. Therefore, just as important as allocating public resources to the development of cooperative housing is ensuring that the latter is protected from recurring dynamics of urban enclosure (Sevilla-Buitrago, 2015).
The risk of commodification of decommodified housing appeared to be an issue everywhere and all cases studied included at least one of three mechanisms to hinder individual capitalization. The first mechanism concerns regulations on the price of shares in cooperative housing models in which members have a share in the cooperative's equity. Usually, the shares cannot be purchased or sold on the open market but, rather, are subjected to price restrictions and, in many cases, members' shares are only updated by the consumer price index. In the case of private housing cooperatives (privat andelsboligforening) in Denmark, for instance, the price of each share must reflect either the initial purchase or construction cost or the property's valuation as a rental building, given that the rental sector is subject to price controls. Subsequent deregulation processes and ambiguities in the maximum price-setting calculations, however, have allowed for a sharp increase in share price ceilings following market dynamics (Larsen & Lund Hansen, 2015, Bruun, 2018, Vidal, 2019a. In Uruguay, in contrast, only a gradual increase in the value of shares is permitted. The latter is calculated by adding the member's initial down payment to the sum of monthly fees they have paid for the principal of the cooperative's mortgage loan, that is, excluding interest (FUCVAM, 2015). Models that do not allow for a real appreciation in the value of cooperative equity shares, in any case, better guarantee long-term housing affordability.
A second set of mechanisms include regulations on monthly quotas or rents and restrictions on subletting housing. In models that do not include equity contributions or include very small, symbolic ones, regulations are focussed mainly on monthly fees and rent. In most of these cases, rental payments are cost-priced. In Quebec, rents for new cooperative developments must fall within 75% to 95% of the area mean price. Over time, this price becomes adjustedwhile still staying within these limitsbased only on the evolution of the cooperative's expenses. 12 In the majority of countries, frameworks also exist to ensure that cooperative housing is the primary residence of members and to hinder any intention to make a profit through regulations on subletting.
The third mechanism concerns restrictions on turning collective ownership models into individual property ownership. Tenure change in this sense is prohibited in cooperatives in Quebec and Denmark. In other cases, this prohibition is limited in time, from 10 years in Austria to 40 years in Germany. In others, tenure change requires special majorities in cooperative assemblies, two-thirds majorities in Switzerland and three fourth majorities in Uruguay. Out of these different types of restrictions, those that are limited in time have proven the least effective in preventing privatisations. In Austria, for example, an estimated third of all cooperative flats are being privatised as residents opt for the 'right to buy' their homes after 10 years (Gruber, 2020, p.49). In the case of New York, out of the 100,000 units of affordable rental and cooperative housing produced by the 1955 Mitchell-Lama programme, only around 45,000 still exist after deregulation from the 1990s onwards (Cabr e, 2020, p. 68). Finally, the majority of cases also involved some degree of regulation on the dissolution of cooperatives, both in terms of allocation of assets in the event of dissolution and subsequent changes to housing tenure, so as to keep assets within the cooperative and non-profit realm. Legal loopholes in this area have nevertheless been exploited, on limited but significant occasions, for speculative practices in countries such as Denmark and Austria (Gruber, 2020, p. 49). Overall, existing public regulations in most cases prove to be a necessary but insufficient factor to guarantee permanent decommodification.

Conclusions
The search for decommodified, affordable and self-managed housing models is a key international political challenge. Faced with new urban enclosures, collective forms of housing production and management have seen a resurgence of comparative scholarship (Czischke et al., 2020;Tummers, 2016) and international political organising, with a particular resurgence of interest in cooperative housing. As debates about the commons increasingly point at a 'double-pronged attack' and a reclaiming of the 'public' (Federici & Caffentzis, 2013), it is essential to gain better understanding of the public-cooperative nexus in its promotion and maintenance. Such an understanding is fundamental in the expansion of those 'hybrid knowledges' that are challenging top-down planning and housing provision through collectively managed and design approaches (Tummers, 2016). By developing a framework that compares public-cooperative policy areas and mechanisms, we examined relations that support not only production, but also, importantly, accessibility and maintenance of the model, across different countries and scales of governance.
With this framework, we make a political intervention following a specific knowledge that is potentially at odds with established traditions of comparative housing policy, by responding to the needs of grassroots groups and intermediaries, and by drawing on the often bottom-up knowledges of practitioners, residents and sympathetic researchers. The first principal contribution of the study in this sense is a broad conceptual framework for understanding the role of the state as a potential enabler of cooperative housing as an affordable and accessible housing alternative. It is important to be aware that in certain policy areas, such as regulations on the access to the cooperative housing stock and those restricting housing equity and the commodification of dwellings, the state might encroach upon key dimensions of the autonomy of cooperatives. These encroachments can be understood as undermining collective self-management, yet might also act as mechanisms through which a wider community claims the 'right not to be excluded' (Blomley, 2016) from cooperative housing commons. The contradictory values, logics and goals involved in the public-cooperative nexus can only really be negotiated in practice. A thorough examination of how these dynamics unfold in the 10 cases studied is beyond the remit of this paper, yet is a crucial avenue for further research.
The second principal contribution of our investigation is a categorisation of concrete policy areas and mechanisms, inductively drawn from 10 different international cases, which are presented as a form of 'advocacy by proxy' for grassroots and right-to-housing organisations, and intended as a higher-level resource and as a starting point for more in-depth studies. The case studies discussed seem to indicate that more coherent alignments between different levels of policy-making as well as sustained societal and sectorial support for the co-operative models were strong indicators of more holistic and long-term public support. A more in-depth examination of the decision-making processes and motivations driving public support for cooperatives remained outside the scope of this study. Recent literature on the emergence and policy recognition of the community-led housing field and its multiple stakeholders (Czischke, 2018;Lang et al., 2020) provides some initial complementary analysis on this issue.
The limitations of the framework proposed may, on a political level, offer new lines of enquiry which can only be addressed through in-depth case study analysis of how to measure the housing commons 'success' of specific policy mechanisms and their interconnection and integration with wider welfare programmes and legislative frameworks: beyond housing production, we believe that scholarship should shift attention to questions of accessibility over time, and the thorny issue of permanent decommodification, in its legal, financial and political dimensions. Such a future enquiry would need to compare the complex interplay, trade-off and negotiations that inform the short and long-term alliances between the state and cooperatives.
Finally, weaknesses and loopholes in publicly-enforced safeguards against commodification, alongside experiences of state deregulation of the cooperative sector, both point towards the importance of engaging in robust nonstate institution-building by cooperative sectors themselves. Such institutions would not per se guarantee permanent decommodification; rather, their design should pre-emptively address shifts in state policy and the tendency to promote member interests over wider social inclusion. Researching safeguards for decommodification put in place by the organisational and institutional structures of cooperative sectors, as well as their development and strength over time, is thus a necessary and promising complementary line of enquiry. The Miethauser Syndicat in Germany, the 'common housing' sector in Denmark and the emerging Community Land Trust movement all stand out as key references in this regard. Their multi-level and multi-stakeholder frameworks make it difficult for any actor to unilaterally appropriate and enclose a part of the sector's housing stock. Further international comparative research on the cooperative side of the public-cooperative nexus can potentially bring out additional tools and strategies to be appropriated for a horizon of permanent decommodification. Notes 1. National, regional and municipal cases included: Denmark, Germany, Austria, Switzerland, Netherlands, United Kingdom, Quebec, Uruguay, Italy (Lazio region) and USA (New York  (Sørvoll and Bengtsson, 2018). According to Ganapati (2010, p. 371), housing cooperatives in India, on the other hand, have been subject to direct state control. 3. In German municipalities such as Hamburg, Berlin, Freiburg, T€ ubingen and Munich, for instance, it is possible to purchase public land for the development of cooperative housing through competitive tender processes based on social and environmental sustainability criteria (H€ olzl & Bernet, 2020). In Lazio, Italy and some Swiss municipalities, housing cooperatives can purchase public land at below market price to develop affordable housing (Rossini, 2020;Thiesen, 2020).

An internationally renown example of the latter is the Portfolio of Properties for Social
Interest Housing (CIVIS) in Uruguay which offers up to 50% of its land and properties for purchase by cooperatives (Mendive, 2013). 5. In the district of Wilhelmsburg, for example, 1,200 out of 5,000 homes in a new development will be reserved for Baugemeinschaften, to be put out to tender in 2020 (IBA Hamburg, 2018), cited in Baiges et al., 2020, p. 19. 6. See Bekendtgørelse af lov om planlaegning [Promulgation of the Planning Act] (2018): §15, Stk. 2. 7. Examples include, in Italy, the 1998 Law of Cooperative auto-recupero (self-refurbishment) in the Lazio region (Rossini, 2020); and in England, since the early 1970s, through municipal governments programmes of temporary transfer of public properties to "shortlife" housing cooperatives (Bowman, 2004;Ferreri and Vasudevan, 2019). 8. Specifically, its Article 18a. The article is further developed in the 2015 Decree on Admitted Institutions for Public Housing (Besluit toegelaten instellingen volkshuisvesting, BTIV) and in the Regulations on Admitted Institutions for 2015 (Regeling toegelaten instellingen, RTIV), cited in Baiges, 2020, p. 75. 9. Through the Acc es Logis Qu ebec programme (SHQ (Societ e d'Habitacion Quebec), 2017b) as cited in Gigling, 2020, p. 86. 10. Between 20% and 50% of cooperative housing subsidised by Acc esLogis must be reserved for homes eligible for the Rental Assistance Programme (SHQ (Societ e d'Habitacion Quebec), 2019), cited in Gigling, 2020, p. 91. 11. See Programmes de renovation (Ville de, 2019), cited in Gigling, 2020, p. 93. 12. In accordance with the requirements of the Acc esLogis Qu ebec programme (SHQ (Societ e d'Habitacion Quebec) 2017a: sec. 5.9-5.10), as cited in Gigling, 2020, p. 83. Lali Dav ı for their support and collaboration during the research project, together with the authors of the different case studies. We also greatly appreciate the helpful feedback from the journal editor Emma Power and three anonymous reviewers.

Disclosure statement
No potential conflict of interest was reported by the author(s).

Funding
The research project was supported by the Generalitat de Catalunya in the framework of the