Innovative housing models to support shared use of space: the case study of Sonnwendviertel Ost in Vienna
Abstract
Amidst the persistent urban expansion in European cities, the need for high-quality housing for growing populations remains a challenge. Integrating newly developed housing areas into the urban fabric and fostering a distinct local identity pose additional challenges. Despite extensive research in this realm, there exists a gap in the examination of the extent of shared space utilization in new housing developments. This study flls that gap by analyzing the quantity, quality, and diversity of space utilization in new housing projects, focusing on the development processes and maintenance methods. The research, conducted through site and case study analyses of Sonnwendviertel Ost development area in Vienna, underscores that the shared utilization of spaces is closely tied to distinct housing models with varied levels of fnancing and involvement of diverse actors. Consequently, it provides insights into the housing models and their confgurations that best facilitate the development of shared use of spaces in housing construction. This, in turn, is perceived as instrumental in cultivating a more robust neighborhood identity and enhancing the livability of communities, thereby contributing to sustainable urban development.
Keywords Housing models, Neighborhood, Urban development, Shared use of space, Vienna, Sonnwendviertel O
Introduction
Due to the growing population in Europe’s major cities, the establishment of new residential housing units has posed a signifcant challenge. In a single year, several hundred thousand housing units are constructed, exemplifed by the realization of 16,528 units in Vienna alone in 2021 (Vollmann 2022). Urban and housing policies exert distinct infuences on the contemporary development of cities (Tosics 2004). Various theoretical approaches exist for facilitating the provision of new dwellings, encompassing the reorganization of existing housing stock, the reuse of former industrial, ofce, and hospital structures, as well as construction on brownfeld or greenfeld sites. Aligned with the intricate framework of sustainability, brownfeld development has been preferred over greenfeld development. Consequently, conscientious policymaking has sought to repurpose brownfelds of former industrial or transportation areas within urban areas for the establishment of new residential neighborhoods. Te primary challenge in the development of housing within these locales lies in their integration into the encompassing urban fabric while cultivating these new units into high-quality, sustainable neighborhoods (Cucca & Friesenecker 2022). Te pursuit is even more challenging due to the need to foster a distinct neighborhood identity. Most of the contemporary housing models are searching for innovation, which is distinctly manifested also in the use of space. But what patterns in the use of space are exhibited by various types of housing models? How do diferent contemporary housing models integrate shared
use of space to enhance the quality and sustainability of urban living environments? To answer these questions, this research aims to explore the connections between housing models and the use of space and uncover the spatial confgurations determined in these housing models. Te research focuses on the shared use of space and applies the sharing-based framework to the analysis of spaces in contemporary housing developments, as it is posited to yield advantageous outcomes at the levels of buildings, neighborhoods, and the broader urban context (Birch 2008; Jarvis 2011; Williams 2007). Te manifestation of sharing within housing projects encompasses both social and physical dimensions across various hierarchical levels. Drawing upon a framework derived from sharing-based co-housing categorization (Babos et al. 2020), this research elucidates the physical dimension of sharing by examining spatial dynamics comparing four tangible housing projects and analyzing the site plan in Sonnwendviertel Ost development area in Vienna. Te analysis extends to the room, building, and land scales, as arguably, the quantity and quality of shared use of space in newly built neighborhoods infuences the way in which they can be woven into the urban fabric and foster a shared identity.
By analyzing the Sonnwendviertel Ost neighborhood in Vienna, the research recognizes Vienna’s historical role as an urban innovation laboratory for new development areas. Notably, over half of the residential units slated for realization between 2014 and 2025 in Vienna are situated within one of its 37 newly established residential neighborhoods (Hofstetter 2020). Simultaneously, Sonnwendviertel Ost neighborhood development ofers an optimal research focus as it has been extensively documented in scholarly publications, delving into the collaborative dynamics among stakeholders engaged in the developmental process and the architectural merit derived from innovative housing models. Te study provides a site analysis of 25 housing projects combined with a comparative analysis of four discrete housing models that are characterized by varying degrees of involvement from the Municipality and other private actors. Consequently, these four housing models serve as an exemplary analytical foundation for investigating the impact of these collaborative arrangements on the confguration of shared spaces within new residences and neighborhoods. Te study addresses two main inquiries. Firstly, it investigates the nature of shared use of space utilization within four distinct housing models to shed light on the models that facilitate higher quantity, quality, and diversity of shared use of spaces. Secondly, it examines whether the development and maintenance process determines the level of space utilization within housing development. Tus, the research ultimately sheds light on the housing models that carry the highest potential for the incorporation of shared use spaces, which are thought to contribute to the integration of new neighborhoods into the existing urban fabric and foster a stronger neighborhood identity. Te analysis posits that a higher degree of municipal support for a project correlates with an increased potential for the manifestation of urban environmental connections through a higher inclusion of shared use of space. Tis assertion stems from the municipality’s stipulated developmental tender requirements concerning public spatial usage, irrespective of fnancial considerations. Te study is limited in its examination of how space sharing contributes to a neighborhood’s integration into the urban fabric, which involves complex processes beyond architectural planning. Further research is needed to explore this aspect within the broader urban context.
Literature review
Te following literature review will cover housing models, the concept of sharing in housing, a sharing-based framework for space categorization, and Vienna’s housing models. Tis section will provide a comprehensive collection of articles and studies that analyze these topics, ofering a substantial overview of the theoretical and practical aspects of shared use of spaces in housing projects. Tis literature review aims to shed light on the principles and practicalities of sharing in housing, summarizing existing research in the feld and identifying the gaps that this study aims to fll, particularly in the context of brownfeld areas with innovative housing solutions like those in Sonnwendviertel Ost.
The categorizations of housing models
Housing models serve as efective tools for evaluating the impact of housing policy on market dynamics, demographic shifts, and economic changes, facilitating comparisons between alternatives, and conducting impact analyses (Priemus et al. 1992). Signifcant contributions to this feld provide insights on housing structure and control (Habraken, 1998), and ofer a broader perspective on urban housing designs (Wolfe, 2008). Additionally, diverse housing models highlight the variety of approaches to incorporating sharing methods, from the Swedish model with a central kitchen to Danish community-oriented designs (Vestbro, 1998). Vestbro’s classifcation outlines fve diferent models of collective housing: central kitchen collective housing, common house collective housing, collective housing with private facilities, tenant cooperatives, and housing cooperatives, each characterized by varying degrees of shared facilities and communal living arrangements (Vestbro, 2010). Te evolving nature of these housing models refects broader social and economic trends, as well as shifts in policy and demographic factors. Housing models were further classifed into specifc sub-types based on user-oriented criteria, including target group, resident profle, level of participation, community building, and sustainability approaches (Tummers 2015), this provides a detailed framework for understanding the nuances and variations within co-housing developments (Tummers 2016). Te sharing-based housing categorization builds on these previous classifcations and frameworks, emphasizing diferent levels and types of sharing in housing projects. In the sharing-based categorization, detailed analyses are provided for housing models such as cohousing, condominium, co-living, collaborative housing, cooperative housing, communal housing, commune, collective living, collective housing, collective self-help housing, collective self-build housing, community-led housing, eco-district, and eco-village (Babos et al. 2020).
The concept of sharing in housing models
Sharing is regarded as a pivotal concern in contemporary urban residential development (Lang et al. 2020), with a substantial body of research exploring its potential benefts. Some of these investigations scrutinize sharing at the project level within residential buildings, documenting positive outcomes such as improvements in social interaction (Bouma and Voorbij 2009), the enhancement of individual well-being (Markle et al. 2015; Carrere Balcells et al. 2020), and the advantages associated with sharing-based economic models and environmental sustainability (Chatterton 2013; McIntosh et al. 2010; Williams 2007). Researches have demonstrated that shared features within residential projects, both in buildings and on building plots, yield neighborhood benefts by fostering increased utilization of public spaces in the community (Roseland 2005; Gehl & Svarre 2013). Furthermore, the presence of shared features has been linked to the emergence of a more diverse range of services (Wehrli-Schindler et al. 2016; Kainz 2023) and to the development of a robust local identity (Schnur 2012). Numerous studies highlight the way in which the culture of sharing in housing projects stimulates citizen participation and proactivity (Fromm 2012; Berggren 2020), ofering alternatives for the use of public land (Gould Ellen and Voicu 2006; Liske 2008), thus underscoring their positive impact at the urban scale as well. Within modern housing development, the manifestation of sharing extends across both physical and social dimensions, encompassing various categories within each dimension (Jarvis 2015). Specifcally, within the realm of social sharing, three distinct categories emerge: shared creation, shared activities, and shared tenure,
each of which exhibits characteristic features within every housing project (Babos et al. 2020). Conversely, the physical dimension introduces categories such as shared use of inside spaces, shared use of outside spaces, and shared use of facilities (Jarvis 2011). In addition to these categorizations, other studies have explored the social and physical dimensions of sharing in housing. Previous research identifed four common characteristics of cohousing developments based on Danish case studies: participatory process, neighborhood design, common facilities, and self-management (McCamant and Durrett 1988). Tis defnition was later expanded with two more key characteristics: the absence of hierarchy and separate incomes (Meltzer 2005). Te previous six characteristics were clarifed and further defned: participatory process, intentional neighborhood design, private homes, and common facilities, resident management, non-hierarchical structure, and no shared incomes (Scotthanson and Scotthanson 2005). According to later studies, fve necessary and sufcient characteristics to defne a cohousing settlement include communitarian multi-functionality, residents’ participation and self-organization, constitutional and operational rules of a private nature, residents’ self-selection, and value characterization (Chiodelli and Bagione 2014). Additionally, secondary features to better describe the sharing concept in housing projects were collected, a proposal classifes the sharing features into four topics: community, housing, design, and context (Giorgi 2020).
Tese comprehensive studies underline the intricate relationship between social and physical dimensions in housing models. It can be asserted that social sharing is contingent upon the existence of the physical dimension, specifcally the shared use of space. Te physical dimension serves as a foundational element in every housing project, albeit in varying quantities and qualities (Widlok 2016). Te existing categorization concept of private, semi-private, semi-public, and public use has a focus on sharing, the pivotal consideration in sharing pertains to “who” utilizes the space (Jackson 1974; Amin 2008; Birch 2008; Sak 2016). Furthermore, the quality of shared use of space difers depending on whether it is an external or internal space, given that the utilization of external spaces is typically transient (Gehl 2001). Te impact of the quantity and quality of the three categories of shared use of space on neighborhood quality has been discussed. A diverse range of private units, designed to suit various life situations, is essential to retain residents in an area and foster a local identity through long-term residence. Common spaces enhance the quality of life for inhabitants, and there is a growing openness among city dwellers to create and utilize such spaces (Kainz 2023). While the urban environment forms the foundation for identity creation, the organizing power, not just the presence of public spaces, is crucial for their efective use (Schnur 2012). Ideally, a combination of top-down support and internal bottom-up needs and eforts is required for optimal outcomes (Schnur & Markus 2010).
Addressing the research gap identifed in the literature review
Building on the insights from the literature review, it is evident that the terminology and categorization of housing models do not explicitly diferentiate between the development process and maintenance method; however, they uniformly refect the application of the sharing concept within residential environments. Contrary to previous research and summaries, this study incorporates both development and maintenance processes within the housing model, thereby ofering a more comprehensive perspective. Many studies summarize the sharing that appear in different models, outlining their potential, rationale, benefts, and drawbacks. Typically, these studies focus on a single housing model, analyzing all its properties, or concentrate on one sharing feature, showcasing all its manifestations. Tis research, however, diverges methodologically and thematically from the existing literature. Instead of a descriptive approach, it uses quantifable methods to analyze spaces, allowing for the examination and comparison of multiple housing models simultaneously, thus ofering a novel perspective based on the literature review. However this study explicitly concentrates on the physical dimension, but the methodology also presents an opportunity for similar analyses of social dimensions. Te examination of shared use space in residential housing projects necessitates a categorization based on sharing principles. In this research, the sharing-based framework builds on the existing concept with a diferent focus: the defnitions of this study aim to address the question of “with whom are spaces shared”. Consequently, it is sharing-based not only user-based, the three categories for evaluating the shared use of space in residential buildings were defned: private, common, and public.
Methodology
The research design Tis study employs the sharing-based framework to analyze the extent of shared use of space utilization in Vienna’s Sonnwendviertel Ost neighborhood in diferent housing models. Te research design consisted of two main phases: the Preparation Phase and the Research and Analysis Phase. To prepare the research as a fundamental step, the sharing-based framework was established and built on the existing categorization concept (see in Literature review) and determined three space categorizations: private, common, and public. The next step in the Preparation Phase involved collecting relevant data for the study area. Since the research aims to examine the relationships between different housing models and space utilization, it was necessary to gather information on both topics. Data were collected, urban plans and architectural drawings were collected, and site visits and interviews were conducted. To facilitate this, a structured data table was created to compile and organize the necessary information. The final step in the Preparation Phase of the research was the development of an area distribution calculation method. This method aligns with the sharing-based framework and enables the calculation and visualization of space distribution both in the site analysis of the neighborhood and within the case study analysis of individual buildings. By incorporating this calculation method, the research ensures a detailed and accurate analysis of how spaces are utilized and shared, providing a clear visual representation of the distribution of private, common, and public spaces.
Te Research and Analysis Phase, involved applying the Area Distribution Calculation method to the collected data, analyzing the spatial distribution patterns, and interpreting the relationships between different housing models and their corresponding space utilization. Firstly, 25 residential building projects are analyzed through site plans, to understand the housing models and their space utilization at the neighborhood level. Secondly, four case studies, each representing distinct housing models, are examined in greater detail. Tis focused investigation aims to provide nuanced insights into the varying degrees of utilization of spaces, taking into account the involvement of diferent public and private actors in their realization. A double approach involving architectural analysis of common interior and exterior spaces in residential buildings developed in the same area but by diferent housing models provides signifcant insights. Troughout the research the double approach is consistently applied, allowing for a comprehensive analysis that captures the complexities of space utilization in diverse models. Tis approach enables a thorough comparison and understanding of how diferent housing models infuence the development and maintenance of shared spaces, further emphasizing the importance of policy in shaping housing models and their outcomes.
Sharing‑based framework for space categorization
In the sharing-based framework the “Private space” refers to space exclusively utilized by an individual or immediate family members. In the context of residential buildings, this typically encompasses the dwelling and its associated areas or enclosed functional units designated for use by a specifc group. “Common space” is a space jointly utilized by members of a group. In residential buildings, these areas are communal and are used collectively by the occupants of the building, distinct from their individual dwellings. “Public space” is accessible to anyone. In residential buildings, functional units designated as public spaces are utilized by residents from the local neighborhood or beyond for specifc functions and are open for use in that particular context. Tis study analyzes the three categories distinctly for both external and internal spaces. External spaces encompass fully open areas, covered spaces, terraces, and balconies within the plot area. Te three designated categories for External spaces are: “private external”, “common external”, and “public external”. Internal spaces are the areas within an enclosed boundary. In our categorization the private internal use subcategories are: “private internal living use”, which is the space of residential units, “private internal other use”, which is the space of other closed functional units and “private internal additional”, which means the additional storage of residential or other functions. Te common internal use subcategories are the spaces of the “common internal foyer”, “common internal storage”, and the “common internal use”. Common foyer is used only by residents, common storage is the space where there are no separate storage units per apartment unit. Te common use is where specifc shared or commonly coordinated use takes place. Te public internal use is divided also into subcategories, “public internal use”, “public internal additional” and “commonly operated public”. Public internal use means the space of the concrete public function, and public internal additional means the spaces added to the concrete function, like storage and foyer. Commonly operated public spaces are those that residents jointly operate or use for business activities.
Site analysis and visualization of shared use of space of the neighborhood
This study entails an examination of shared use of space in housing development, encompassing a comprehensive analysis of 25 residential projects to ofer an inclusive overview of the overall built-up area. Firstly, fundamental data and materials pertaining to all housing projects were collected and systematized, based on the project website (Living in Sonnwendviertel—Territory Support of Urban Renewal), concomitant with an analysis of space utilization at the site plan scale. Tus, sharing-based space utilization diagrams were generated from a structured data table containing project-specifc details, including housing model, development process, maintenance method, commencement and delivery year, designer, investor, plot size, built-up area, number of apartments, other private functions, types of common and public functions, and their level-specifc representation. Shared space utilization diagrams were crafted using the open-source map database of Vienna GIS (Te City of Vienna—Geographical Information System). Te analysis of shared use of space involved recording private, common, and public spaces on building and land levels. To facilitate comparison, diagrams were drawn by the author to represent the similar way the spatial division by the publicness. Te delineation of space usage specifcs relied on architectural drawings analysis, supplemented by periodic on-site surveys and photomaking conducted during the neighborhood’s construction years —specifcally, on September 14, 2020, September 11, 2021, September 10, 2022, and December 20, 2023.
Criteria of the case studies selection and their analysis
Additionally to the site analysis, four projects (plots and their buildings) were selected by the case study selection criteria system. A case study analysis was conducted at the room, building, and land scale, involving the selection of four representative projects to discern the interplay between distinct housing models and shared use of space. Tese case studies epitomize the enduring housing models within the area, developed as part of the comprehensive Sonnwendviertel Ost residential neighborhood plan developed between 2015 and 2016. Te area was subsequently constructed between 2016 and 2023, with each plot featuring a comparable size (ranging from 1600 to 2200 m2 ) comprising a singular block of fats with 5–8 stories and a basement. Te analysis of space utilization entailed a comparative evaluation of the dimensions of private, common, and public spaces, both internal and external. Area distribution calculations were executed using a proprietary area distribution calculation method. based on edited schematic foor plans for each case study. Te area enclosed by the primary structures was computed to determine the size of functional units, with net square meters aggregated by type. All functions were categorized as private, common, or public based on their shared use, excluding the garage function due to its indistinct use type. Troughout the analysis, the proportional representation of each shared use of space type, both internal and external, was calculated in relation to the overall space. Te analysis culminated in a comparative assessment of the proportions of spaces across the four selected projects, elucidating variations in shared utilization.
Results
The site and case study analysis, summed up in Table 1, revealed that in the case of the “Fully subsidized social housing” model encompassing social housing, there is a prevalence of larger apartments, limited shared spaces on the ground foor, and a signifcant allocation to public external spaces. Buildings belonging to the “Partially subsidized cohousing” model, such as cohousing projects, exhibit a diverse array of shared spaces, emphasizing community functions across various levels and public functions at street level. Multifunctional buildings belonging to the “Limited free fnanced multifunctional housing” model strike a balance, incorporating private, common, and shared spaces across all foors. Apartment structures under the “Free fnanced apartment housing” model, conversely, prioritize private living and minimize communal and public spaces, likely infuenced by their commercial nature in terms of realization and upkeep. Te results of the analysis of sharing-based space utilization in diferent housing models indicate variations in the occurrence, quantity, and quality of private, shared, and public spaces. Te examination of diferent housing models unveils distinctive patterns in shared use of space, infuencing the integration of new brownfeld housing development neighborhoods into the urban fabric and contributing signifcantly to the reinforcement of local identities—a crucial aspect of urban life.
A notable result of the analysis is that housing models with moderate subsidies, particularly “Partially subsidized cohousing” and “Limited free fnanced multifunctional housing”, demonstrate a greater abundance and diverse array of shared spaces in various locations. Several factors may contribute to this observation. Primarily, both models diminish the central role of the Municipality, allowing private actors to introduce innovation and diverse perspectives to housing projects through policies and tender specifcations. Consequently, the involvement of private entities enhances the potential for creative solutions in housing construction. Additionally, in cohousing projects falling under the partially subsidized model, engaging communities in shaping their daily lives fosters a heightened sense of local solidarity, encouraging the incorporation of innovative and vital neighborhood functions. On the contrary, “Fully subsidized social housing” and “Free fnanced apartment housing” models demonstrate a considerably reduced quantity, quality, and diversity in shared spaces, both common and public. Tis phenomenon can be linked to the specifc goals and purposes of buildings falling under these models. Social housing units are constructed by the Municipality with the aim of providing high-quality and afordable housing to a broad population, inherently limiting opportunities for innovation and space sharing. In the case of apartment buildings under the free fnanced housing model, the low level of innovation and community functions likely stems from the primary goal of maximizing returns within defned conditions.
Hence, the research suggests that it is potentially more efective for municipalities to endorse and support innovation in housing rather than directly attempting innovation. Te participation of diverse actors, including communities in the development process, innovative architectural ofces, non-proft developers, and others, nurtures a heightened sense of creativity and a willingness to explore new ideas. Concurrently, the Municipality assumes a crucial role in not completely ceding housing construction and maintenance to for-proft developers. Tey may prioritize their individual interests and might be less aligned with the broader interests of a building, neighborhood, and the city, particularly in terms of longterm sustainable urban development and the cultivation of vibrant local communities. Tankfully, innovative initiatives, such as cohousing and multifunctional building projects have received stronger support due to the quality assurance procedures between 2015 and 2017, detailing the criteria of competition tenders, with the specifc aim of identifying exceptional projects that exhibit a high-quality mix of uses. By using a variety of tailor-made tenders, the underlying concept posits that a harmonious blend of unconditionally sold plots and those adhering to specifc criteria, “the gems of the neighborhood as it were -, would contribute to the overall creation of a vibrant and urban city district. Initial observations provide grounds to anticipate outstanding outcomes.” (Robert Temel in Hartmann et al 2020).
Te four case studies, each representing a distinct housing model, efectively substantiate and illustrate the site analysis fndings on sharing-based space utilization. Notably, the moderate subsidy models, exemplifed by “Partially subsidized cohousing” and “Limited free fnanced multifunctional housing”, consistently demonstrate richer and more diverse shared use of spaces, aligning with the site analysis observations. In contrast, the “Fully subsidized social housing” and “Free fnanced apartment housing” models exhibit a diminished presence of shared uses, confrming the link between specifc housing goals and the quantity, quality, and variety of shared spaces within the projects. Furthermore, the analysis of internal and external space utilization reveals signifcant trends in how diferent housing models prioritize space. Projects such as Schöne
Table 1: Characteristics of Sharing-Based Space Utilization of the Four Housing Models Derived from the Site Analysis
Source: Own editing from own database
| Housing Models | Private Internal Spaces | Private External Spaces | Common Internal Spaces | Common External Spaces | Public Internal Spaces | Public External Spaces |
|---|---|---|---|---|---|---|
| Fully Subsidized Social Housing | In a large proportion, larger-sized apartments predominantly on upper floors | In a large proportion, small balconies on upper floors | In a small proportion, small spaces related to household management and corridors on the ground floor | No or in small proportion, corridors or recreational spaces on upper floors | In a small proportion, social service functions on the ground floor | In a large proportion, parks and playgrounds on the ground floor |
| Partially Subsidized Cohousing | In a moderate proportion, mixed-sized apartments on upper floors | In a small proportion, small balconies on upper floors | In a large proportion, spaces related to household management, corridors, additional convenience functions on the ground and upper floors | In a large proportion, corridors and recreational areas on upper floors | In a moderate proportion, cultural, community, educational, and service functions in the basement and on the ground floor | In a large proportion, community garden, recreational, and service-related areas on the ground floor |
| Limited Free Financed Multifunctional Housing | In a moderate proportion, medium-sized apartments on upper floors | In a small proportion, small balconies on upper floors | In a small proportion, recreational and corridor areas on upper floors | In a moderate proportion, recreational and corridor areas on upper floors | In a large proportion, cultural and service functions in the basement, ground floor, and upper floors | In a large proportion, community garden, recreational, and service-related areas on the ground floor and upper floors |
| Free Financed Apartment Housing | In a large proportion, small and medium-sized apartments on the ground and upper floors | In a large proportion, small balconies and garden on the ground and upper floors | In a small proportion, corridor on upper floors | In a large proportion, garden on the ground floor | Not at all or in a small proportion, large-sized shops or services on the ground floor | Not at all or in a small proportion, corridors on the ground floor |
Aussichten and Favorita III show a substantial increase in private space utilization in their external areas, highlighting a preference for personal spaces among residents. Conversely, projects like Haus am Park continue to allocate a notable portion of their external space for public use, indicating a commitment to community-oriented spaces. Tese fndings suggest that the degree of subsidy and the housing model signifcantly infuence not only the presence of shared spaces but also how these spaces are utilized, thus impacting the overall living experience of the residents.
Discussion The housing development area: Sonnwendviertel Ost, Vienna
The Vienna Housing Policy Model, which outlines the approach to constructing and subsidizing social housing in Vienna, has gained international recognition (Elsinga et al. 2014). Since 1920, the City of Vienna has implemented its social housing program, with evolving objectives and tools across diferent periods: providing housing on a social basis from 1920 to 1950, creating high-quality public housing from 1950 to 1980, and diversifying public housing from 1980 to 1995 (Klein 2012). In 1995, the contemporary Vienna Housing Policy Model was introduced in response to the continual growth of Vienna, emphasizing integration and identity in urban planning (Lévy-Vroelant et al. 2008). Tis shift resulted in a nuanced housing policy integrated into urban planning, incorporating innovative housing models (Marquardt & Glaser 2020). Approximately 60% of residents reside in apartments owned or supported by the municipality at subsidized rents, with the municipality owning 220,000 dwellings and limited-proft housing companies owning 200,000 (Province of Vienna 2023).
Within the Housing Policy Model, the initial objective of increasing the number of high-quality dwellings through residential building construction has evolved into a more comprehensive initiative. Currently, there is a pressing need to seamlessly integrate housing structures into the broader urban development landscape (Kadi 2018). Te establishment and maintenance of these innovative neighborhoods rely on housing models guided by specifc concepts for individual building projects (Förster et al. 2016). Te Policy Model entails guideline-based and site-specifc development areas, continually incorporating innovative housing models. Te housing models undergo constant improvement through project monitoring and leveraging experiential insights (Förster et al. 2016, 2018). Experts, developers, and local governments view the ongoing housing development in the Model as a form of urban laboratory (Bitter & Weber 2009).
The Sonnwendviertel development area is in Vienna’s 10th district were formerly dedicated to railway storage and transport functions. In 2000, the Austrian Federal Railways (ÖBB) released the area surrounding the station, which had become obsolete. Te development of the site aimed to achieve two primary objectives dictated by its location. Firstly, it sought to repurpose the brownfeld area with new functions, and secondly, it aimed to establish a novel urban area connecting the 10th district with the city center (see Fig. 1). Conceptual plans for the area were formulated in 2004, and ongoing discussions with neighboring residents throughout the process. Te zoning plan was ultimately fnalized in 2012 through collaborative eforts involving six architectural frms. Among the innovative developments is the Sonnwendviertel development area, consisting of four distinguishable phases in concept and development time: Sonnwendviertel West I, Sonnwendviertel West II, Sonnwendviertel Ost, and the Helmut Zilk Park (see Fig. 2). Te initial two phases of blockscale housing developments were implemented at various stages through a concept competition within a subsidized housing model, complemented by an educational block. In contrast, the third phase involves building-scale housing developments under four distinct long-term housing models and one short-term housing model (E. Gruber et al. 2022).
The design phase for the housing projects in Sonnwendviertel Ost commenced in mid-2015, following the fnalization of the master plan. Construction commenced at the end of 2016, with varying starting points and schedules for each project, ultimately reaching full completion by autumn 2023. Sonnwendviertel Ost encompasses residential development (1,500 dwellings) and workplace development (2200 work areas) (Gruber 2021). Given the diverse development processes and maintenance methods applied, this area serves as a canvas for innovative housing solutions, guided by design objectives that prioritize functional diversity, active street and ground-foor usage, fexible foor plans, an agreeable level of urban density, and community engagement (Szabó & Babos 2020). Consequently, this locale proves conducive to spotlighting the distinctive characteristics of shared use of space as identifed by the various housing models.
Housing models in Sonnwendviertel Ost To foster innovative housing projects for the optimal use of urban public property, the Sonnwendviertel area employs four long-term housing models (WohnService Wien, 2017). Te specifcs of these models draw from prior innovative urban developments in Vienna (RevenHolzmann, 2019). Te four models analyzed in this study
employ the city of Vienna’s categorization based on the way in which the land is allocated for development and the extent of subsidy from the local government (Temel 2019). Building maintenance during the utilization phase is strongly correlated to the way in which it is developed (see Fig. 2). It is important to note that there is a ffth model specifcally for short-term housing, such as for hotels, student housing, and service apartment housing. Buildings belonging to this model are developed and maintained based on the developing private company’s overall profle, and their services are tailored and maintained according to the target group. As this model is outside the scope of the current study which focuses on long-term housing, it is only briefy touched upon in the analysis.
Under the “Fully subsidized social housing” model, housing is developed and fnanced by the municipality, remains under municipal maintenance and is not sold. In this model, the municipality retains ownership of the plot and constructs a building on it. Since the property is fully owned and maintained by the municipality, it is operated by a municipal property maintenance company. Tis model usually encompasses social housing units, designed to provide housing for socially deprived individuals with municipal support. Tis model is represented by 2 projects in the analysis. Te “Partially subsidized cohousing” model encompasses community-oriented housing projects with rents below the market rate due to municipal subsidies. Under this approach, the municipality issues a tender for the utilization of the plot under diferent themes. Te building is then constructed and operated by a developer, while the property remains in the ownership of the municipality. Tis model encompasses cohousing buildings, aimed at ensuring the participation of residents in their creation and the collective use and ownership of spaces.Tis model is represented by 3 projects in the analysis. Te “Limited free fnanced multifunctional housing” model incorporates projects featuring individually rented dwellings, rentals by a proft-limited company, as well as community-owned or privately purchased units. In this model, the municipality announces a tender for the sale of the plot under diferent project themes. Te developer owns the property, but the project must be constructed and operated according to the tender specifcations. Tis model encompasses multifunctional housing buildings, intended to create permanent workplaces in addition to regular housing functions. Tis model is represented by 9 projects in the analysis.
Projects under the “Free fnanced apartment housing” model are designated for market rent or sale. Tis model involves the municipality selling the plot entirely to a developer who then constructs a building on it. Since the developer owns the property, decisions regarding sale, rent, and building operation are made by the developer. On the one hand, this model features apartment housing buildings, providing convenient residential apartments with additional features. Long-term residential
apartment housing is represented by 7 projects in the analysis. On the other hand, short-term housing projects, such as hotels, dormitories and serviced apartments are also within this category.Tese are operated and designed based on a private company’s overall profle, while services are tailored and maintained according to the company’s main target group. Tis subcategory is represented by 4 projects in the spatial analysis, and is excluded from case study analysis because it is out of the scope of the research.
Site analysis of the 25 housing projects In the analysis of the Sonnwendviertel Ost neighborhood, shared use of space was distinguished into private, common, and public categories. Private spaces encompass residential units as well as private ofces, studios, or workshops. Common interior spaces vary across diferent residences, encompassing amenities such as pram storage, bicycle storage, party rooms, ftness facilities, saunas, community kitchens, Airbnb units, laundry rooms, children’s rooms, workshops, and libraries. Conversely, common external spaces exhibit similarities, including roof terraces, roof gardens, and playgrounds. Te public category of shared use of space pertains to spaces accessible not only to the residents of a building but to the broader public as well. Te diversity of public space utilization, both internal and external, is pronounced in Sonnwendviertel Ost. Examples include exercise rooms, coworking spaces, multifunctional rooms, general practitioner ofces, retail establishments, laundries, package receiving rooms, restaurants, cafes, bicycle services, and art studios.
The utilization of space at the street level displays a mixed pattern across the 25 residential buildings in Sonnwendviertel Ost, both in internal and external public spaces. 13 of these buildings allocate the ground foor for completely or partially private purposes, such as residential or other private functions. Additionally, several residential buildings incorporate both common (6 projects) and public (17 projects) spaces on the ground foor. Notably, a total of 4 instances exhibits multiple shared uses within a single foor of a building. Regarding external spaces, about half of the them are in public use, in 13 projects are the external ground foor on common use or enclosed garden areas designated for private units (see Ground foor in Fig. 3). Analysis of basement and the frst foor (as a general upper foor) plans reveals that public spaces extend either below or above street level in 6 projects. All 25 buildings analyzed feature fat roofs, enabling the utilization of the upper foor (see Basement, First foor in Fig. 3). However, in 2 cases, it serves as a terrace for private units, while in 7 instances, it functions as a common lounge, garden, or roof terrace (see Rooftop in Fig. 3). Te upper foors are reserved for private utilization in most cases, as that is where most dwelling units are situated.
Case study analysis of selected housing projects
To highlight the distinct sharing-based space utilization characteristics identifed by the four housing models in the site analysis and to substantiate fndings, four longterm housing case studies were specifcally chosen to represent the distinct housing models within the area. Te selected projects include Schöne Aussichten belonging to the “Fully subsidized social housing” model (22.B plot), Gleis21 belonging to the “Partially subsidized cohousing” model (17.C plot), Haus am Park belonging to the “Limited free fnanced multifunctional housing” model (17.B plot), and Favorita III belonging to the “Free fnanced apartment housing” model (18.B plot) (see Fig. 4). A data summary table has been compiled, providing essential information about each case study, including the housing model, development process, maintenance method, as well as the types and quantities of private, common, and public spaces (see Table 2 and Fig. 5). Additionally, foor plan analyses have been conducted for each building level, illustrating the quantitative and qualitative attributes of private, common, and public spaces (see Fig. 6).
Schöne Aussichten, falling under the “Fully Subsidized social housing” model, was fnalized in 2019 through the
eforts of the Vienna municipality, and is currently managed by one of the municipality’s property maintenance entities. Te primary objective of this project was to ofer high-quality and afordable housing to socially disadvantaged individuals. Private internal spaces constitute 68% of the internal areas, encompassing apartments and their associated small storage units. Notably, these private units often feature balconies, collectively covering 32% of the external spaces. Te project comprises a total of 67 apartments, with an average size of 80.30 square meters and a diverse range of sizes varying from 45 to 95 square meters. Common space utilization within this project is confned to the laundry room, storage areas, and corridors, accounting for 18% of the external space and 12% of the internal space. Overall, 57% of the external spaces are designated for public use, while 13% of the internal spaces are allocated for public purposes. Public facilities encompass creative spaces, a development school for youth and parents, an open playground, and a park, the building forms a L-shaped confguration. Tis layout fosters an open and secure communal utilization of space within the neighborhood.
Gleis 21, falling under the “Partially subsidized cohousing” model, operates through the Gleis21 Residential Cooperative, leasing each apartment as a partially subsidized rental. Te project is designed to foster community living, encourage participation, and provide access to cultural services for residents in the neighborhood. Private spaces, representing the apartments, constitute 57% of the internal spaces, while apartment balconies contribute 11% to the external spaces. Te project comprises 34 apartments, with an average size of 78.68 square meters and a diverse range spanning from 38 to 110 square meters. A variety of common spaces are incorporated, including a communal kitchen, children’s room, sauna, workshop, library, guest apartment, bicycle storage, storage room, laundry room, and a roof terrace. Tese common spaces cover 21% of the internal space and 26% of the external space. Public spaces within the design focus on cultural, educational, and community facilities,
Table 2: Basic Information and Functions of Private-Common-Public Space Utilization in the Selected Case Studies
Source: Own editing
| Housing Models | CODE of the Plot | Name of the Project | Architecture Office | Developer | Maintainer | Move-in Date | Flat Number | Office Unit Number | Private Functions | Common Functions | Public Functions |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fully Subsidized Social Housing | C.22.B | Schöne Aussichten | ASAP | EBG | Municipal property maintenance company | 2019 | 67 | 0 | Storage, laundry room | Developing school for youngsters and parents, playground, park | |
| Partially Subsidized Cohousing | C.17.C | Gleis 21 | einszueins architektur | Schwarzatal | Gleis21 Residential Cooperative | 2019 | 34 | 0 | Community kitchen, children room, roof terrace, sauna, workshop, library, Airbnb flat, bicycle garage, storage, laundry room | Music school, gastronomy, event space, media workshop, multifunctional room, studio | |
| Limited Free Financed Multifunctional Housing | C.17.B | Haus am Park | feld72 Architekten | Kallinger | Authorized maintenance company by the owners | 2018 | 29 | 3 | Bicycle garage, storage | Dancing studio, “chilletarium”, art gallery, co-working, roof garden for urban gardening | |
| Free Financed Apartment Housing | C.18.B | Favorita III | Werkstatt Grinzing | WBV-GFW | Authorized maintenance company by the developer | 2018 | 45 | 3 | Storage, garden |
featuring a music school, café, event space, media room, and multifunctional hall. Public spaces account for 21% of the internal spaces and 57% of the external spaces. Te inclusion of covered public spaces on the ground foor and diverse shared use of space contribute to strengthening relationships within the neighborhood and fostering community development through endowing publicly accessible places with a clear neighborhood-level funcion.
Haus am Park, falling under the “Limited free fnanced multifunctional housing” model, employs a mixed maintenance method. In this project, 12 apartments and 3 ofce spaces are available for rent, while 17 are privately owned, with an external property management company overseeing maintenance on behalf of the owners. Te project was designed to establish a well-organized residential building with a balanced mix of uses, encompassing private, common, and public spaces in appropriate proportions. Private spaces constitute 51% of the internal spaces, while balconies and terraces for the private units contribute to 21% of the external spaces. Te 29 apartments, with an average size of 70.69 square meters, range from 53 to 90 square meters. Common internal space usage constitutes 16% of the total internal space, emphasizing storage, circulation, and recreational areas, with common terraces covering 21% of the external space. Public spaces, on the other hand, ofer a diverse range of facilities such as the “Chilletarium,” dance studio, art gallery, co-working service, and urban gardening features on the roof garden. Public utilization accounts for 33% of the internal space, while the ground foor and roof terraces on diferent levels collectively represent 58% of the external space. Tis arrangement of public and common spaces on various levels, moving shared use away from the street level, serves as an illustrative example of innovative solutions that provide benefts to residents at the neighborhood level.
Favorita III falls under the “Free fnanced apartment housing” model, with a mixed maintenance approach. It features 43 apartments for rent, while 2 apartments and 3 ofces are privately owned. Te primary objective of the project was to establish a high-quality residential building with substantial ofce spaces. Te average apartment size is 58.29 square meters, ranging between 40 and 70 square meters. Private internal areas constitute a signifcant portion at 91%, encompassing storage spaces associated with the apartments an ofces. External private areas, including balconies and garden spaces linked to private units, make up 35% of the external spaces. Shared circulation and storage areas contribute to 9% of the internal space, with the shared external garden occupying 57%. Notably, the building lacks public internal spaces, with external spaces representing only 8% of the exterior space. Te design incorporates a small covered open space on the ground foor, with enclosed massing at the corner to reinforce the protection of private functions.
Conclusion
As European cities grapple with the ongoing challenge of continuous expansion, the demand for high-quality housing for growing populations remains constant. Tis challenge becomes particularly pronounced when incorporating newly constructed neighborhoods into the broader urban context. Despite signifcant research in this domain, there is a notable gap in the research pool of the impact of shared use of space through the application of sharing-based space analysis, despite the comprehensive framework it provides. Tus, the incorporation of sharing-based analysis, coupled with site and case study analyses, covers this research gap by revealing optimal strategies for housing development in urban environments. A diverse array of publicly accessible spaces within an area contributes to the formation of local communities, with shared use of both internal and external
spaces enhancing diversity in terms of function, design, maintenance, and user engagement. Thus, the quantity and quality of shared spaces shape the process of integration of new neighborhoods into the urban fabric and fostering a distinctive local identity—essential elements for sustainable urban development. This study focuses on the development area of the Sonnwendviertel Ost in Vienna, recognized as an innovative best-practice large-scale development project. It examines shared use of space using four distinct housing development and maintenance models: “Fully subsidized social housing”, “Partially subsidized cohousing”, “Limited free fnance multifunctional housing”, and “Free fnanced apartment housing” The analysis of sharing-based space utilization involved categorizing spaces into private, common, and public, and the methodology relied on site analysis encompassing 25 buildings and case study analysis focusing on 4 housing projects, each representing a specifc development process and maintenance method. The study has found diverse manifestations of shared use of space in the study area, with common and public spaces positively infuencing neighborhood livability. The internal public spaces are predominant in projects with moderate municipal support, namely projects belonging to the “Partially subsidized cohousing” and “Limited free fnanced multifunctional housing” models respectively. In contrast, projects driven by market forces or entirely managed by the municipality prioritize private inside spaces available for rent or sale. Tis includes housing projects in the “Fully subsidized social housing” and the “Free fnanced apartment housing” models, resulting in fewer and less impactful neighborhood-level advantages. However, the amount of external public space in “Fully subsidized social housing” in the analyzed project is high, but it is also not diverse and unused. Several factors contribute to this observation, including the overarching goal of housing project development. Municipalities aim to provide high-quality housing for a broad population, prioritizing space for private uses. Private developers, driven by proft and usage, also tend to focus on the provision of high-quality private spaces over public ones. Tis approach addresses the paradox discussed by Kainz (2023), where privately developed housing gains value through diversity, even though these projects may not contribute substantially to shared value. Additionally, the mix of actors involved in moderately supported housing projects, such as innovative communities, architectural ofces, non-proft developers, and other housing experts fosters creativity and experimentation beyond the capabilities of municipal bodies in terms of both development and maintenance.
The study concludes that municipalities should support innovative housing development with higher space sharing for neighborhood integration and local identity creation. Concurrently, municipalities should retain their vital role in infuencing housing construction to align with the broader interests of the city. Fortunately, Vienna has endeavored to achieve this goal through a diverse set of tender criteria, with which it simultaneously infuences innovation and diversity for higher community value. Community-oriented projects are recognized as pivotal by experts, playing a key role in the implementation and long-term maintenance of common and public spaces. Continuous monitoring and improvement, driven by the diversity of innovative projects, contribute to the area’s identity and usability
This study addresses the research questions posed in the introduction by demonstrating that shared spaces signifcantly enhance the integration of new neighborhoods into the urban fabric. Best practices for designing and maintaining these spaces include ensuring a mix of private, common, and public spaces, supported by municipal policies that foster innovation and community engagement. Collaboration between municipalities and private developers is essential to create diverse and inclusive shared spaces that cater to a broad range of users. Te fndings underscore the importance of municipal support in promoting shared spaces, which ultimately contributes to sustainable urban development. The limitation of this study pertains to the investigation of the impact of publicly accessible spaces’ quality, quantity, and diversity on a neighborhood’s integration into the broader urban fabric. Tis integration is infuenced by complex, interconnected processes that extend beyond the scope of architectural planning. Therefore, additional research is needed to explore this aspect within the broader context of urban dynamics. Te study recommends that future site-level spatial planning should encompass not only functional concepts but also provide a coherent defnition of shared spaces in the context of site interactions. This approach is crucial for ensuring the creation of high-quality neighborhoods and addressing fundamental questions about shared space use. Beyond presenting fndings, the study serves as a guide for future urban planning strategies, contributing to the global discussion on housing challenges. By refecting on the ongoing evolution and innovation in Vienna’s urban landscape, the insights from the study lay the foundation for sustainable, inclusive, and resilient neighborhoods that are integrated into the urban fabric.
Declarations
Availability of Data and Materials
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.Competing Interests
The authors declare that they have no competing interests.Funding
Not applicable.Author’s Contributions
AB collected the data, analyzed, and interpreted the site plan and floor plans. AB and MB developed the methodology. AO and MB gathered the theoretical background. All authors read and approved the final manuscript.Acknowledgements
Not applicable.Authors’ Information
Not relevant.Received: 5 February 2024
Accepted: 23 July 2024
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