The act of housing The development of a space-time relationship was a revolution during the Modern Movement. How to incorporate the time variable into architecture became a fundamental matter throughout the twentieth century and became the focus of the Team 10’s research and practice. Following this concern, Herman Hertzberger tried to adapt to the change and growth of architecture by incorporating spatial polyvalency in his projects. During the post-war period,  and as response to the fast and homogeneous urbanization developed using mass production technologies, John Habraken published “The three R’s for Housing” (1966) and “Supports: an Alternative to Mass Housing” (1961). He supported the idea that a dwelling should be an act as opposed to a product, and that the architect’s role should be to deliver a system through which the users could accommodate their ways of living. This means allowing personal expression in the way of inhabiting the space within the limits created by the building system. To do this, Habraken proposed differentiating between 2 spheres of control: the support which would represent all the communal decisions about housing, and the infill that would represent the individual decisions. The Diagoon Houses, built between 1967 and 1971, follow this warped and weft idea, where the warp establishes the main order of the fabric in such a way that then contrasts with the weft, giving each other meaning and purpose.   A flexible housing approach Opposed to the standardization of mass-produced housing based on stereotypical patterns of life which cannot accommodate heterogeneous groups to models in which the form follows the function and the possibility of change is not considered, Hertzberger’s initial argument was that the design of a house should not constrain the form that a user inhabits the space, but it should allow for a set of different possibilities throughout time in an optimal way. He believed that what matters in the form is its intrinsic capability and potential as a vehicle of significance, allowing the user to create its own interpretations of the space. On the same line of thought, during their talk “Signs of Occupancy” (1979) in London, Alison and Peter Smithson highlighted the importance of creating spaces that can accommodate a variety of uses, allowing the user to discover and occupy the places that would best suit their different activities, based on patterns of light, seasons and other environmental conditions. They argued that what should stand out from a dwelling should be the style of its inhabitants, as opposed to the style of the architect. User participation has become one of the biggest achievements of social architecture, it is an approach by which many universal norms can be left aside to introduce the diversity of individuals and the aspirations of a plural society.   The Diagoon Houses, also known as the experimental carcase houses, were delivered as incomplete dwellings, an unfinished framework in which the users could define the location of the living room, bedroom, study, play, relaxing, dining etc., and adjust or enlarge the house if the composition of the family changed over time. The aim was to replace the widely spread collective labels of living patterns and allow a personal interpretation of communal life instead. This concept of delivering an unfinished product and allowing the user to complete it as a way to approach affordability has been further developed in research and practice as for example in the Incremental Housing of Alejandro Aravena.  Construction characteristics The Diagoon Houses consist of two intertwined volumes with two cores containing the staircase, toilet, kitchen and bathroom. The fact that the floors in each volume are separated only by half a storey creates a spatial articulation between the living units that allows for many optimal solutions. Hertzberger develops the support responding to the collective patterns of life, which are primary necessities to every human being. This enables the living units at each half floor to take on any function, given that the primary needs are covered by the main support. He demonstrates how the internal arrangements can be adapted to the inhabitants’ individual interpretations of the space by providing some potential distributions. Each living unit can incorporate an internal partition, leaving an interior balcony looking into the central living hall that runs the full height of the house, lighting up the space through a rooflight.   The construction system proposed by Herztberger is a combination of in-situ and mass-produced elements, maximising the use of prefabricated concrete blocks for the vertical elements to allow future modifications or additions. The Diagoon facades were designed as a framework that could easily incorporate different prefabricated infill panels that, previously selected to comply with the set regulations, would always result in a consistent façade composition. This allowance for variation at a minimal cost due to the use of prefabricated components and the design of open structures, sets the foundations of the mass customization paradigm.   User participation While the internal interventions allow the users to covert the house to fit their individual needs, the external elements of the facade and garden could also be adapted, however in this case inhabitants must reach a mutual decision with the rest of the neighbours, reinforcing the dependency of people on one another and creating sense of community. The Diagoon Houses prove that true value of participation lies in the effects it creates in its participants. The same living spaces when seen from different eyes at different situations, resulted in unique arrangements and acquired different significance. User participation creates the emotional involvement of the inhabitant with the environment, the more the inhabitants adapt the space to their needs, the more they will be inclined to lavish care and value the things around them. In this case, the individual identity of each household lied in their unique way of interpreting a specific function, that depended on multiple factors as the place, time or circumstances. While some users felt that the house should be completed and subdivided to separate the living units, others thought that the visual connections between these spaces would reflect better their living patterns and playful arrangement between uses.   After inhabiting the house for several decades, the inhabitants of the Diagoon Houses were interviewed and all of them agreed that the house suggested the exploration of different distributions, experiencing it as “captivating, playful and challenging”1. There was general approval of the characteristic spatial and visual connection between the living units, although some users had placed internal partitions in order to achieve acoustic independence between rooms. One of the families that had been living there for more than 40 years indicated that they had made full use of the adaptability of space; the house had been subject to the changing needs of being a couple with two children, to present when the couple had already retired, and the children had left home. Another of the families that was interviewed had changed the stereotypical room naming based on functions (living room, office, dining room etc.) for floor levels (1-4), this could as well be considered a success from Hertzberger as it’s a way of liberating the space from permanent functions. Finally, there were divergent opinions with regards to the housing finishing, some thought that the house should be fitted-out, while others believed that it looked better if it was not conventionally perfect. This ability to integrate different possibilities has proven that Hertzberger’s experimental houses was a success, enhancing inclusivity and social cohesion. Despite fitting-out the inside of their homes, the exterior appearance has remained unchanged; neighbourly consideration and community identity have been realised in the design. The changes reflecting the individual identity do not disrupt the reading of the collective housing as a whole.   Spatial polivalency in contemporary housing From a contemporary point of view, in which a housing project must be sustainable from an environmental, social and economic perspective, the strategies used for the Diagoon Houses could address some of the challenges of our time. A recent example of this would be the 85 social housing units in Cornellà by Peris+Toral Arquitectes, which exemplify how by designing polyvalent and non-hierarchical spaces and fixed wet areas, the support system has been able to accommodate different ways of appropriation by the users, embracing social sustainability and allowing future adaptations. As in Diagoon, in this new housing development the use of standardized, reusable, prefabricated elements have contributed to increasing the affordability and sustainability of the dwellings. Additionally, the use of wood as main material in the Cornellà dwellings has proved to have significant benefits for the building’s environmental impact. Nevertheless, while this matrix of equal room sizes, non-existing corridors and a centralised open kitchen has been acknowledged to avoid gender roles, some users have criticised the 13m² room size to be too restrictive for certain furniture distributions. All in all, both the Diagoon houses and the Cornellà dwellings demonstrate that the meaning of architecture must be subject to how it contributes to improving the changing living conditions of society.  Although different in terms of period, construction technologies and housing typology, these two residential buildings show strategies that allow for a reinterpretation of the domestic space, responding to the current needs of society.  

The housing crisis After the crisis of 2008, it became obvious that the mainstream mechanisms for the provision of housing were failing to provide secure and affordable housing for many households, especially in the countries of the European south such as Spain. It is in this context that alternative forms emerged through social initiatives. La Borda is understood as an alternative form of housing provision and a tenancy form in the historical and geographical context of Catalonia. It follows mechanisms for the provision of housing that differ from predominant approaches, which have traditionally been the free market, with a for-profit and speculative role, and a very low percentage of public provision (Allen, 2006). It also constitutes a different tenure model, based on collective instead of private ownership, which is the prevailing form in southern Europe. As such, it encompasses the notions of community engagement, self-management, co-production and democratic decision-making at the core of the project. Alternative forms of housing In the context of Catalonia, housing cooperatives go back to the 1960s when they were promoted by the labour movement or by religious entities. During this period, housing cooperatives were mainly focused on promoting housing development, whether as private housing developers for their members or by facilitating the development of government-protected housing. In most cases, these cooperatives were dissolved once the promotion period ended, and the homes were sold. Some of these still exist today, such as the “Cooperativa Obrera de Viviendas” in El Prat de Llobregat. However, this model of cooperativism is significantly different from the model of “grant of use”, as it was used mostly as an organizational form, with limited or non-existent involvement of the cooperative members. It was only after the 2008 crisis, that new initiatives have arisen, that are linked to the grant-of-use model, such as co-housing or “masoveria urbana”.  The cooperative model of grant-of-use means that all residents are members of the cooperative, which owns the building. As members, they are the ones to make decisions about how it operates, including organisational, communitarian, legislative, and economic issues as well as issues concerning the building and its use. The fact that the members are not owners offers protection and provides for non-speculative development, while actions such as sub-letting or transfer of use are not possible. In the case that someone decides to leave, the flat returns to the cooperative which then decides on the new resident. This is a model that promotes long-term affordability as it prevents housing from being privatized using a condominium scheme. The grant -of -use model has a strong element of community participation, which is not always found in the other two models. International experiences were used as reference points, such as the Andel model from Denmark and the FUCVAM from Uruguay, according to the group (La Borda, 2020). However, Parés et al. (2021) believe that it is closer to the Almen model from Scandinavia, which implies collective ownership and rental, while the Andel is a co-ownership model, where the majority of its apartments have been sold to its user, thus going again back to the free-market stock. In 2015, the city of Barcelona reached an agreement with La Borda and Princesa 49, allowing them to become the first two pilot projects to be constructed on public land with a 75-year leasehold. However, pioneering initiatives like Cal Cases (2004) and La Muralleta (1999) were launched earlier, even though they were located in peri-urban areas. The main difference is that in these cases the land was purchased by the cooperative, as there was no such legal framework at the time. This means that these projects are classified as Officially Protected Housing (Vivienda de Protección Oficial or VPO), and thus all the residents must comply with the criteria to be eligible for social housing, such as having a maximum income and not owning property. Also, since it is characterised as VPO there is a ceiling to the monthly fee to be charged for the use of the housing unit, thus keeping the housing accessible to groups with lower economic power. This makes this scheme a way to provide social housing with the active participation of the community, keeping the property public in the long term. After the agreed period, the plot will return to the municipality, or a new agreement should be signed with the cooperative. The neighbourhood movement In 2011, a group of neighbours occupied one of the abandoned industrial buildings in the old industrial state of Can Batlló in response to an urban renewal project, with the intention of preserving the site's memory (Can Batlló, 2020; Girbés-Peco et al., 2020). The neighbourhood movement known as "Recuperem Can Batlló" sought to explore alternative solutions to the housing crisis of the time. The project started in 2012, after a series of informal meetings with an initial group of 15 people who were already active in the neighbourhood, including members of the architectural cooperative Lacol, members of the labour cooperative La Ciutat Invisible, members of the association Sostre Civic and people from local civic associations. After a long process of public participation, where the potential uses of the site were discussed, they decided to begin a self-managed and self-promotion process to create La Borda. In 2014 they legally formed a residents’ cooperative and after a long process of negotiation with the city council, they obtained a lease for the use of the land for 75 years in exchange for an annual fee. At that time, the group expanded, and it went from 15 members to 45. After another two years of work, construction started in 2017 and the first residents moved in the following year. The participatory process The word “participation” is sometimes used as a buzzword, where it refers to processes of consultation or manipulation of participants to legitimise decisions, leading it to become an empty signifier. However, by identifying the hierarchies that such processes entail, we can identify higher levels of participation, that are based on horizontality, reciprocity, and mutual respect. In such processes, participants not only have equal status in decision-making, but are also able to take control and self-manage the whole process. This was the case with La Borda, a project that followed a democratic participation process, self-development, and self-management. An important element was also the transdisciplinary collaboration between the neighbours, the architects, the support entities and the professionals from the social economy sector who shared similar ideals and values.                    According to Avilla-Royo et al. (2021), greater involvement and agency of dwellers throughout the lifetime of a project is a key characteristic of the cooperative housing movement in Barcelona. In that way, the group collectively discussed, imagined, and developed the housing environment that best covered their needs in typological, material, economic or managerial terms. The group of 45 people was divided into different working committees to discuss the diverse topics that were part of the housing scheme: architecture, cohabitation, economic model, legal policies, communication, and internal management. These committees formed the basis for a decision-making assembly. The committees would adapt to new needs as they arose throughout the process, for example, the “architectural” committee which was responsible for the building development, was converted into a “maintenance and self-building” committee once the building was inhabited. Apart from the specific committees, the general assembly is the place, where all the subgroups present and discuss their work. All adult members have to be part of a committee and meet every two weeks. The members’ involvement in the co-creation and management of the cooperative significantly reduced the costs and helped to create the social cohesion needed for such a project to succeed. The building After a series of workshops and discussions, the cooperative group together with architects and the rest of the team presented their conclusions on the needs of the dwellers and on the distribution of the private and communal spaces. A general strategy was to remove areas and functions from the private apartments and create bigger community spaces that could be enjoyed by everyone. As a result, 280 m2 of the total 2,950 m2 have been allocated for communal spaces, accounting for 10% of the entire built area. These spaces are placed around a central courtyard and include a community kitchen and dining room, a multipurpose room, a laundry room, a co-working space, two guest rooms, shared terraces, a small community garden, storage rooms, and bicycle parking. La Borda comprises 28 dwellings that are available in three different typologies of 40, 50 and 76 m2, catering to the needs of diverse households, including single adults, adult cohabitation, families, and single parents. The modular structure and grid system used in the construction of the dwellings offer the flexibility to modify their size in the future. The construction of La Borda prioritized environmental sustainability and minimized embedded carbon. To achieve this, the foundation was laid as close to the surface as possible, with suspended flooring placed a meter above the ground to aid in insulation. Additionally, the building's structure utilized cross-laminated timber (CLT) from the second to the seventh floors, after the ground floor made of concrete. This choice of material had the advantage of being lightweight and low carbon. CLT was used for both the flooring and the foundation The construction prioritized the optimization of building solutions through the use of fewer materials to achieve the same purpose, while also incorporating recycled and recyclable materials and reusing waste. Furthermore, the cooperative used industrialized elements and applied waste management, separation, and monitoring. According to the members of the cooperative (LaCol, 2020b), an important element for minimizing the construction cost was the substitution of the underground parking, which was mandatory from the local legislation when you exceed a certain number of housing units, with overground parking for bicycles. La Borda was the first development that succeeded not only in being exempt from this legal requirement but also in convincing the municipality of Barcelona to change the legal framework so that new cooperative or social housing developments can obtain an “A” energy ranking without having to construct underground parking. Energy performance goals focused on reducing energy demands through prioritizing passive strategies. This was pursued with the bioclimatic design of the building with the covered courtyard as an element that plays a central role, as it offers cross ventilation during the warm months and acts as a greenhouse during the cold months. Another passive strategy was enhanced insulation which exceeds the proposed regulation level. According to data that the cooperative published, the average energy consumption of electricity, DHW, and heating per square meter of La Borda’s dwellings is 20.25 kWh/m², which is 68% less, compared to a block of similar characteristics in the Mediterranean area, which is 62.61 kWh/m² (LaCol, 2020a). According to interviews with the residents, the building’s performance during the winter months is even better than what was predicted. Most of the apartments do not use the heating system, especially the ones that are facing south. However, the energy demands during the summer months are greater, as the passive cooling system is not very efficient due to the very high temperatures. Therefore, the group is now considering the installation of fans, air-conditioning, or an aerothermal installation that could provide a common solution for the whole building. Finally, the cooperative has recently installed solar panels to generate renewable energy. Social impact and scalability According to Cabré & Andrés (2018), La Borda was created in response to three contextual factors. Firstly, it was a reaction to the housing crisis which was particularly severe in Barcelona. Secondly, the emergence of cooperative movements focusing on affordable housing and social economies at that time drew attention to their importance in housing provision, both among citizens and policy-makers. Finally, the moment coincided with a strong neighbourhood movement around the urban renewal of the industrial site of Can Batlló. La Borda, as a bottom-up, self-initiated project, is not just an affordable housing cooperative but also an example of social innovation with multiple objectives beyond providing housing. The group’s premise of a long-term leasehold was regarded as a novel way to tackle the housing crisis in Barcelona as well as a form of social innovation. The process that followed was innovative as the group had to co-create the project, which included the co-design and self-construction, the negotiation of the cession of land with the municipality, and the development of financial models for the project. Rather than being a niche project, the aim of La Borda is to promote integration with the neighbourhood. The creation of a committee to disseminate news and developments and the open days and lectures exemplify this mission. At the same time, they are actively aiming to scale up the model, offering support and knowledge to other groups. An example of this would be the two new cooperative housing projects set up by people that were on the waiting list for la Borda. Such actions lead to the creation of a strong network, where experiences and knowledge are shared, as well as resources. The interest in alternative forms of access to housing has multiplied in recent years in Catalonia and as it is a relatively new phenomenon it is still in a process of experimentation. There are several support entities in the form of networks for the articulation of initiatives, intermediary organizations, or advisory platforms such as the cooperative Sostre Civic, the foundation La Dinamo, or initiatives such as the cooperative Ateneos, which were recently promoted by the government of Catalonia. These are also aimed at distributing knowledge and fostering a more inclusive and democratic cooperative housing movement. In the end, by fostering the community’s understanding of housing issues, and urban governance, and by seeking sustainable solutions, learning to resolve conflicts, negotiate and self-manage as well as developing mutual support networks and peer learning, these types of projects appear as both outcomes and as drivers of social transformation.

Background An aspect that is worth highlighting of Marmalade Lane, the biggest cohousing community in the UK and the first of its kind in Cambridge, is the unusual series of events that led to its realisation. In 2005 the South Cambridgeshire District Council approved the plan for a major urban development in its Northwest urban fringe. The Orchard Park was planned in the area previously known as Arbury Park and envisaged a housing-led mix-use master plan of at least 900 homes, a third of them planned as affordable housing. The 2008 financial crisis had a profound impact on the normal development of the project causing the withdrawal of many developers, with only housing associations and bigger developers continuing afterwards. This delay and unexpected scenario let plots like the K1, where Marmalade Lane was erected, without any foreseeable solution. At this point, the city council opened the possibilities to a more innovative approach and decided to support a Cohousing community to collaboratively produce a brief for a collaborative housing scheme to be tendered by developers. Involvement of users and other stakeholders   The South Cambridgeshire District Council, in collaboration with the K1 Cohousing group, ventured together to develop a design brief for an innovative housing scheme that had sustainability principles at the forefront of the design. Thus, a tender was launched to select an adequate developer to realise the project. In July 2015, the partnership formed between Town and Trivselhus ‘TOWNHUS’ was chosen to be the developer. The design of the scheme was enabled by Mole Architects, a local architecture firm that, as the verb enable indicates, collaborated with the cohousing group in the accomplishment of the brief. The planning application was submitted in December of the same year after several design workshop meetings whereby decisions regarding interior design, energy performance, common spaces and landscape design were shared and discussed. The procurement and development process was eased by the local authority’s commitment to the realisation of the project. The scheme benefited from seed funding provided by the council and a grant from the Homes and Communities Agency (HCA). The land value was set on full-market price, but its payment was deferred to be paid out of the sales and with the responsibility of the developer of selling the homes to the K1 Cohousing members. Who, in turn, were legally bounded to purchase and received discounts for early buyers. As relevant as underscoring the synergies that made Marmalade Lane’s success story possible, it is important to realise that there were defining facts that might be very difficult to replicate in order to bring about analogue housing projects. Two major aspects are securing access to land and receiving enough support from local authorities in the procurement process. In this case, both were a direct consequence of a global economic crisis and the need of developing a plot that was left behind amidst a major urban development plan. Innovative aspects of the housing design Spatially speaking, the housing complex is organised following the logic of a succession of communal spaces that connect the more public and exposed face of the project to the more private and secluded intended only for residents and guests. This is accomplished by integrating a proposed lane that knits the front and rear façades of some of the homes to the surrounding urban fabric and, therefore, serves as a bridge between the public neighbourhood life and the domestic everyday life. The cars have been purposely removed from the lane and pushed into the background at the perimeter of the plot, favouring the human scale and the idea of the lane as a place for interaction and encounters between residents. A design decision that depicts the community’s alignment with sustainable practices, a manifesto that is seen in other features of the development process and community involvement in local initiatives. The lane is complemented by numerous and diverse places to sit, gather and meet; some of them designed and others that have been added spontaneously by the inhabitants offering a more customisable arrangement that enriches the variety of interactions that can take place. The front and rear gardens of the terraced houses contiguous to the lane were reduced in surface and remained open without physical barriers. A straightforward design decision that emphasises the preponderance of the common space vis-a-vis the private, blurring the limits between both and creating a fluid threshold where most of the activities unfold. The Common House is situated adjacent to the lane and congregates the majority of the in-doors social activities in the scheme, within the building, there are available spaces for residents to run community projects and activities. They can cook in a communal kitchen to share both time and food, or organise cinema night in one of the multi-purpose areas. A double-height lounge and children's playroom incite gathering with the use of an application to organise easily social events amongst the inhabitants. Other practical facilities are available such as a bookable guest bedroom and shared laundry. The architecture of its volume stands out due to its cubic-form shape and different lining material that complements its relevance as the place to convene and marks the transition to the courtyard where complementary outdoor activities are performed. Within the courtyard, children can play without any danger and under direct supervision from adults, but at the same time enjoy the liberty and countless possibilities that such a big and open space grants. Lastly, the housing typologies were designed to recognise multiple ways of life and needs. Consequently, adaptability and flexibility were fundamental targets for the architects who claim that units were able to house 29 different configurations. They are arranged in 42 units comprehending terraced houses and apartments from one to five bedrooms. Residents also had the chance to choose between a range of interior materials and fittings and one of four brick colours for the facade. Construction and energy performance characteristics Sustainability was a prime priority to all the stakeholders involved in the project. Being a core value shared by the cohousing members, energy efficiency was emphasised in the brief and influenced the developer’s selection. The Trivselhus Climate Shield® technology was employed to reduce the project’s embodied and operational carbon emissions. The technique incorporates sourced wood and recyclable materials into a timber-framed design using a closed panel construction method that assures insulation and airtightness to the buildings. Alongside the comparative advantages of reducing operational costs, the technique affords open interior spaces which in turn allow multiple configurations of the internal layout, an aspect that was harnessed by the architectural design. Likewise, it optimises the construction time which was further reduced by using industrialised triple-glazed composite aluminium windows for easy on-site assembly. Furthermore, the mechanical ventilation and heat recovery (MVHR) system and the air source heat pumps are used to ensure energy efficiency, air quality and thermal comfort. Overall, with an annual average heat loss expected of 35kWh/m², the complex performs close to the Passivhaus low-energy building standard of 30kWh/m² (Merrick, 2019). Integration with the wider community It is worth analysing the extent to which cohousing communities interact with the neighbours that are not part of the estate. The number of reasons that can provoke unwanted segregation between communities might range from deliberate disinterest, differences between the cohousing group’s ethos and that one of the wider population, and the common facilities making redundant the ones provided by local authorities, just to name a few. According to testimonies of some residents contacted during a visit to the estate, it is of great interest for Marmalade Lane’s community to reach out to the rest of the residents of Orchard Park. Several activities have been carried out to foster integration and the use of public and communal venues managed by the local council. Amongst these initiatives highlights the reactivation of neglected green spaces in the vicinity, through gardening and ‘Do it yourself’ DIY activities to provide places to sit and interact. Nonetheless, some residents manifested that the area’s lack of proper infrastructure to meet and gather has impeded the creation of a strong community. For instance, the community centre run by the council is only open when hired for a specific event and not on a drop-in basis. The lack of a pub or café was also identified as a possible justification for the low integration of the rest of the community. Marmalade Lane residents have been leading a monthly ‘rubbish ramble’ and social events inviting the rest of the Orchard Park community. In the same vein, some positive impact on the wider community has been evidenced by the residents consulted. One of them mentioned the realisation of a pop-up cinema and a barbecue organised by neighbours of the Orchard Park community in an adjacent park. Perhaps after being inspired by the activities held in Marmalade Lane, according to another resident.

A response to environmental and economic challenges The initiators of Patch22, architect Tom Frantzen and building manager Claus Oussoren, aimed at achieving together what they couldn’t manage in previous commissions independently: an oversized wooden structure characterised by flexibility, distinctive architecture, and a strong commitment to sustainability. They established the development company Lemniskade Projects to pursue their goals (Frantzen et al architecten, 2017). Winning the Amsterdam Buiksloterham Sustainability tender in 2009, Patch22 was not only recognised for its exceptional sustainability scores but also for its innovative circular design approach and its capability to adapt to unforeseen future uses. The project's primary objectives were rooted in environmental sustainability, employing renewable and reusable materials, particularly wood for the main structure and facade. Embracing Open Building principles, Patch22 sought maximum flexibility in dwelling sizes and layouts, offering an ingenious response to the environmental and economic challenges outlined in the tender (Kendall, 2021). The 30-meter-tall wooden structure currently hosts 33 dwellings with diverse sizes ranging from 40 m² to 204 m². The building promotes long-term adaptability, as it is prepared to be easily subdivided into six independent office floors or a maximum of 48 apartments (Frantzen, 2023). This showcases how a single support structure can serve multiple generations, accommodating the dynamic needs of its users while addressing some of the current environmental challenges such as material waste, the construction industry’s carbon footprint or the implementation of design for disassembly practices.     A flexible and adaptable building A flexibility of a building can be enhanced when traditional architectural elements are reassessed. Various strategies were employed to maximize the adaptability of use, layout design, and apartment sizes: No load-bearing division walls The timber laminated post and beam structure, in combination with lightweight division walls, became crucial to ensure size variations between apartments and a greater freedom of choice in defining the layouts. Additionally, by superimposing the residential and office regulations, introducing a generous floor height of 4 m, and structurally supporting floor loads of 4 KN, the building accommodates the potential for entirely or partially utilising residential spaces for office purposes (Frantzen et al architecten, 2017). No vertical shafts inside the apartment In conventional housing, meter cabinets, kitchens, and bathrooms have typically been constructed near vertical shafts to minimise the length of the drains. When developing Patch22, it was unknown which units would merge to form a single apartment, making it challenging to position the vertical shafts. Two shafts were integrated into the structural core, with pre-installed drains, water and electricity conduits running up to each front door, from where they could be extended to the desired location in an apartment (Council on Open Building, 2023). Hollow floors to run services horizontally Patch22 adopts a horizontal services distribution, a common practice in office buildings. The necessary inclination of a toilet drain from the central shaft to the outermost corner of the building results in a floor build-up increase to 50cm. This available space for conduits enables the placement of kitchens and bathrooms anywhere within the dwelling. This departure from the traditional clustering of humid spaces in residential buildings facilitates the creation of multiple floor layouts that respond to the users’ needs. No meters inside the apartment By relocating the heavily regulated meters and main switches to the ground floor and placing the non-regulated secondary fuse boxes at each level, Patch22 provides open spaces which can be subdivided in multiple ways (Frantzen, 2023). The independence of the meters from the dwellings streamlines future adaptations with minimal disruptions to the individual living spaces. Smaller subdivision of legal entities From a technical perspective, designing a flexible and adaptable building is feasible. But it is also necessary to provide the legal mechanisms that make it possible. In the case of Patch22, each floor contains 8 legal units that can be combined horizontally or vertically (Frantzen, 2023). Although, in its current state, most floors have 3-6 dwellings per flight, these legal units could be divided or merged, sold, or rented independently, used as office or as residential spaces. Designing for the unknown Embracing the philosophy advocated by Habraken (OpenBuilding.co, 2023), Patch22 prioritises designing for the unknown. Strategies include over-dimensioning the structure, simultaneous compliance with diverse regulations for different uses, incorporating extra entrance doors, and providing space for additional mailboxes. These approaches keep the design open for future changes, ensuring long-term adaptability.     A sustainable proposal Patch22 embodies sustainability across multiple dimensions.  Environmentally, the building achieves sustainability through a series of strategies: improving energy efficiency, using renewable materials, and fostering layout flexibility. The 2009 design garnered a GPR score of 8.9 and an EPC of 0.2, showcasing its commitment to sustainable practices. The roof, covered with photovoltaic panels, makes the building energy-neutral, while the rainwater collection feeds into a grey water system. The adoption of CO2-neutral pellet stoves, utilising compressed waste wood as fuel, further underlines Patch22’s commitment to eco-friendly energy sources (Frantzen et al architecten, 2017). Despite the challenges posed by fire and acoustic regulations, the building boldly features wood as its main material, with additional thickness added to columns and beams to comply with safety standards. This decision, although increasing costs, remains more economical than the alternative solution of building with 2D CLT panels (Frantzen, 2023). Additionally, the emphasis on long-term layout flexibility aligns with environmental sustainability by reducing waste during future adaptations and facilitating component disassembly. From a social standpoint, involving residents in the design process fostered diversity and strengthened the sense of belonging. Finally, the economic sustainability of Patch22 is evident in its adaptable support, serving as a long-term investment that evolves with changing needs, potentially acquiring different uses over time, benefitting both the planet and the economic interests of its users. Construction characteristics The support components, encompassing the structure, façade, and core of Patch22, are highly prefabricated, facilitating a swift and precise assembly process on-site while minimising waste and reducing disruptions. The structure incorporates over-dimensioned laminated wooden beams and columns, along with vertical core constructed with prefabricated concrete panels (Open Building NOW!, 2020). The NW and SE façades employ CLT panels with a thickness of 220mm, while the NE and SW orientations, serving as the main facades, create loggias on both sides. The loggia's interior façade features modulated sliding doors with CLT prefabricated frames, allowing for the free placement of interior partitions by strategically positioning mullions every 3 meters (Frantzen, 2023). Externally, the loggia is characterised by redwood truss beams with bolted connections to steel joints which facilitate their future disassembly. These buffer zones can be fully enclosed with glazed modular panels in winter or left open with a fixed handrail during the summer. The floor plays a pivotal role in leveraging the flexibility of the apartments within the structure. Employing a Slimline structural flooring system made of IPE 400 steel profiles and a 70mm reinforced concrete slab below, this design allows services to run efficiently within the hollow floor, reaching even the most remote corners of each apartment. After installing drains and other facilities, the floor is topped with an acoustic membrane, a Lewis profile sheet, and 8cm of anhydrite screed with underfloor heating. While initially considering demountable top floor tiles, this solution was deemed complex and expensive compared to the anhydrite screed, which proved more cost-effective and flexible (Frantzen, 2023). By planning in advance for the placement of maintenance registration points to the floor cavity, it was possible to enable access for the necessary alterations while maintaining practicality and affordability.    User customisation process The customisation process at Patch22 began with a search for prospective residents through social media, leveraging it as a platform to connect with individuals interested in actively designing their living spaces in collaboration. Once on board, residents were presented with the opportunity to shape their homes within an entirely empty interior. A catalogue of multiple variations was offered by the architects, allowing some residents to select a pre-designed option that suited their preferences. Alternatively, others opted for a more collaborative approach, working closely with Frantzen architects to create a custom layout. Some residents took an independent venue, either designing their dwellings themselves or hiring another architect to develop their interiors (Frantzen, 2023). Throughout the process, Frantzen provided comprehensive guidance on the technical requirements, ensuring compliance with fire and soundproofing regulations. Residents could choose to have the base installations in the floor installed by the main contractor or to receive the bare shell and install them themselves. This inclusive approach allowed residents to actively contribute to the unique character of Patch22 while ensuring the resiliency of the building support for future generations.

Background The soaring housing shortage in the Netherlands has prompted national and local governments to come up with innovative solutions to cater for the ever-increasing demand. The Flexwonen model is a response to the need to provide homes quickly and to foster circularity and innovation in the construction sector. The model is crafted to meet the housing needs of people who cannot simply wait for the lengthy process of conventional housing developments or cannot afford to remain on the endless waiting list to be allocated a home. Flexibility is its main characteristic. This is reflected not only in the design and construction features of the housing buildings, but also in the regulatory frameworks that make them possible. The faster the units are built and delivered, the greater the impact on people’s lives. This dynamic approach, which adapts to existing and evolving circumstances of homebuilding, relies on collaboration between stakeholders in the sector to streamline the procurement and building process. All of this is accompanied by an integrated approach to placemaking, exemplified by the partnership with a local social organisation, the involvement of a community builder, the provision of spaces for residents to interact and get to know each other, the project's target groups and the beneficiary selection process. Flexwonen can have a significant impact on municipalities and regions that are severely affected by housing shortages, especially those lacking sufficient land and time to develop traditional housing projects. Due to its temporary nature, homes can be built on land that is not suitable for permanent housing. This streamlines the building process and allows the development of areas that are not currently suitable for housing, both in urban and peri-urban zones. After the initial site permit expires, the homes can be moved to another site and permanently placed there. Recent developments in construction techniques and materials contribute to raising the aesthetic and quality standards of these projects to a level equivalent to that of permanent housing, as the case of Oosterdreef in Nieuw-Vennep demonstrates. Nevertheless, this model, propelled by the government in 2019 with the publication of the guide ‘Get started with flex-housing!’ and the ‘Temporary Housing Acceleration taskforce’ in 2022 (Druta & Fatemidokhtcharook, 2023), is still at an embryonic stage of development. The success of the initiative and its real impact, especially in the long term, remain to be seen. Analogous housing projects have been carried out in other European countries, such as Germany, Italy, and France among others (See references section). Although their objectives and innovative aspects resonate with the ones of Flexwonen in the Netherlands, the nationwide scope of this model, sustained by the commitment and collaboration between national and local governments, social housing providers and contractors, is taking the effects of policy, building and design innovation to another level. Involvement of stakeholders The national government's aim to establish a more dynamic housing supply system, capable of adapting to local, regional or national demand trends in the short-term, has prompted municipalities like Haarlemmermeer to join forces with housing corporations. Together, they venture into the production of housing that can leverage site constraints while contributing to bridging the gap between supply and demand in the region.   Thanks to its innovative, flexible and collaborative nature, the Oosterdreef project was completed in less than a year after the first module was placed on the site. The land, which is owned by the municipality, is subject to environmental restrictions due to the noise pollution caused by its proximity to Schiphol airport, meaning that the construction of permanent housing was not feasible in the short term. Nevertheless, the pressing challenge of providing housing, especially for young people in the region, priced out by the private market, has led the municipality to collaborate with a housing corporation and an architecture firm. Together, they have developed a ‘Kavelpaspoort’ (plot passport), a document that significantly expedites the building process. The plot passport is a comprehensive framework that summarises a series of requirements, restrictions, guidelines and details in a single document, developed in consultation with the various stakeholders involved. Its main purpose is to expedite the construction process. Its various benefits include helping to shorten the time it takes for the project to be approved by the relevant authorities, facilitating the selection of a suitable developer and contractors, and avoiding unforeseen issues during construction. The document is also an effective means of incorporating the voices of relevant stakeholders, including local residents before any work begins on the site. This ensures transparency and participatory decision-making. In Oosterdreef, Ymere, the housing corporation that manages the units, and FARO, the architecture firm commissioned with the design, played pivotal roles in drafting the document in collaboration with the municipality of Haarlemmermeer. Their main objective was to swiftly build houses using innovative construction techniques and to provide much-needed housing on a site that was underused due to land restrictions. Project’s target groups and selection process Perhaps one of the most compelling aspects of the model is the diverse group of people it intends to benefit. The target groups of Flexwonen vary according to context and needs, as the municipalities are in charge of establishing their priorities. In the case of Oosterdreef, Ymere and Haarlemmermeer aim for a social mix that not only contributes to solving the housing shortage in the region, but also supports the integration process of the status holders. The selection of status holders, i.e. asylum seekers who have received a residence permit and therefore cannot continue living in the reception centres, who would benefit from the scheme, was carried out in collaboration with the municipality and the housing corporation. As most of these residents did not previously live in the local area, as the central government determines the number of status holders that each municipality must accommodate, the social mix is attained by also including local residents. In this case, they were allocated a flat in the project based on a specific profile, as the flats were designed for single people. The project, which comprises 60 dwellings, is therefore deliberately divided to accommodate 30 of the above-mentioned status holders and 30 locals. In addition, the group of locals was completed with emergency seekers (‘Spoed- zoekers’) and starters. The emphasis that the project's focus on this population swathe emphasises its social function. Emergency seekers are people who are unable to continue living in their homes due to severe hardship, including circumstances that severely affect their physical or mental well-being, and who are otherwise likely to be at risk of homelessness. This includes, for example, victims of domestic violence and eviction, but also people going through a life-changing situation such as divorce. On the other hand, starters, in this project between the ages of 23 and 28, refer to people who long to start on the housing ladder, e.g., recent graduates, young professionals, migrant workers and people who are unable to move from their parental home to independent living due to financial constraints. Finally, local residents interested in the project were asked to submit a letter of motivation explaining how they would contribute to making Oosterdreef a thriving community, in addition to the usual documentation required as part of the process. Thus, a stated willingness to participate in the project was deemed more important than, for example, a place on the waiting list, demonstrating the commitment of the housing corporation and local authorities to creating a community and placemaking. Innovative aspects of the housing design Although this model has been applied to a range of buildings and contexts, from the temporary use of office space to the retrofitting of vacant residential buildings and the use of containers in its early stages of development (which has had a significant bearing on the stigmatisation of the model), one of the most notable features of the government's current approach to scaling up and accelerating the model is its support for the development of innovative construction techniques. The use of factory-built production methods such as prefabricated construction in the form of modules that are later transported to the site to be assembled could help to establish the model as a fully-fledged segment of the housing sector. An example of this is Homes Factory, a 3D module factory based in Breda, which was chosen as the contractor. Prefab construction not only significantly reduces the construction phases, but also makes it easier to relocate the houses when the licence expires after 15 years, which contributes to its flexibility. The architecture firm FARO played a crucial role in shaping the plot passport, which incorporated details on the design and layout of the scheme. The objective was to encourage social interaction through shared indoor and outdoor spaces, organized around two courtyards. These courtyards are partially enclosed by two- and three-storey blocks, featuring deck access with wider-than-usual galleries with benches that offer additional space for the inhabitants to linger. Additionally, facilities such as letterboxes, entrance areas, waste collection points, and covered bicycle parking spaces were strategically placed to foster spontaneous encounters between neighbours. Some spaces, such as the courtyards, were intentionally left unfinished to encourage and enable residents to determine the function that best suits them. This provides an opportunity for residents to get to know each other, integrate, and cultivate a sense of belonging. Within the blocks, the prefab modules consist of two different housing typologies of 32 m2 and 37 m2. One of these units on the ground floor was left unoccupied to be used as a common indoor space. The ‘Huiskamer’ or living room according to its English translation, is strategically located at the heart of the scheme, adjacent to the mailboxes and bicycle parking space. Besides serving as a place for everyone to meet and hold events, it is the place where a community builder interacts and works with the residents on-site. Construction and energy performance characteristics The environmental sustainability of the building was at the top of the project's priorities. Off-site construction methods offer several advantages over traditional techniques, including reduced waste due to precise manufacturing at the factory, efficient material transport, less on-site disruption, shorter construction times and the reusability and circularity of the materials and the units themselves. The choice of bamboo for the façades also contributes to the project's sustainability. Bamboo is a highly renewable and fast-growing material compared to traditional timber, with a low carbon footprint as it absorbs CO2 during growth (linked to embodied carbon). It also has energy-efficient properties, such as good thermal regulation, which leads to lower energy consumption (operational carbon). This is complemented by a heat pump system and solar panels on the roofs of the buildings. “The only thing that is not permanent is the site” This sentiment was shared by many, if not all, individuals involved in the project whom I had the opportunity to interview for this case study. The design qualities of the project meet the standards expected for permanent housing. One of the main challenges faced by projects of this type is the perception, increasingly erroneous, that their temporary nature implies lower quality compared to permanent housing. In this case, the houses were designed and conceived as permanent dwellings, the temporary aspect is only linked to the site. When the 15-year licence expires, the homes will be relocated to another location where they can potentially become permanent. They can also be reassembled in a different configuration if required, a possibility granted by the modular design of the dwellings. Integration with the community The residents were selected with the expectation that they would contribute to building a community and support the permit-holders to better adapt and integrate into the local community and surroundings. Ymere, together with a local social organisation, helps new residents in this process of integration. During the first two years following the completion of the construction phase, concurrent with tenants moving into their new homes, an on-site community builder works with residents to help them forge the social ties that will enable the development of a cohesive and thriving community. The community builder has organised a range of social activities and initiatives in collaboration with the residents in the shared spaces. These include piano lessons, communal meals, sporting activities and ‘de Weggeefkast’, or the giveaway cupboard, a communal pantry aimed at fostering a sense of neighbourly sharing and cooperation.