Social change processes are a constant challenge for urban planning. After all, urban planning is not a silent observer of society, but plays a decisive role in shaping it at the spatial level. With regard to the issue of single-family homes, our initial observation is that urban planning is still in its discovery phase. This is surprising in view of the otherwise heated debate about its future: How does urban planning actually assess this form of living and settlement? What potential and risks do single-family home neighbourhoods hold for the spatial development of municipalities? What answers does urban planning have for aging and shrinking single-family housing estates?

Often labelled as a prohibition policy, municipalities are increasingly juggling with legal options in order to respond to the contradictory challenges of limited space for urban growth, affordable housing and continuing demand for single-family housing estates. However, in other places, there is a consensus about a supposed desire for expulsion, in which even vacancies close to the city centre are not a sufficient argument for a prioritised inner development policy. Urban planning then finds itself in an ambivalent position. In some municipalities, for example, clear planning attitudes can be seen to be against single-family homes. Given the political decision-making power and fundamental urban restructuring processes, however, these appear to have little power of enforcement. Elsewhere, it is the internalised single-family house policy of urban planning itself that helps to determine municipal urban development policy.

Against this backdrop, this collective article takes a closer look at planning approaches and possible courses of action in response to the specific challenges posed by single-family homes. Our article presents four final theses that were written between 2022 and 2023 as part of the Master's and Bachelor's degree programmes in Urban Planning at Bauhaus University.

The contributions are what the planning theorist Peter Marcuse might call critical planning (see Progressive Planning 2010). They stand for an understanding of planning that opposes rational and technical planning and sets itself the task of analysing, disclosing, proposing and ultimately politicising.

The following articles begin by soberly analysing the single-family home and raise various social and ecological issues, such as the aggravation of wealth inequalities or urban sprawl. Due to their construction and location, single-family housing estates are highly inefficient compared to denser residential neighbourhoods, particularly in terms of energy consumption and transport routes. The research is based on a growing number of scientific studies that address the social challenges of single-family homes (e.g. ARL 2018; Berndgen-Kaiser 2012; Wüstenrot Foundation 2012, 2016).

By disclosing, Marcuse means the task of planning to communicate the results of these analyses in an understandable way and to point out their consequences. The following papers show that ideas of socio-ecological settlement development are difficult to reconcile with the single-family home and what long-term consequences this has for spatial development.

An important part of the final papers are concrete proposals and realistic approaches on how to address these challenges. How can single-family housing estates look and be planned in the future? What structural and spatial form could they take, who would own them and the land beneath them and what planning instruments would be used to achieve this? The politicisation of single-family homes and the formulation of alternative futures, as Marcuse ultimately calls for, means that these questions are discussed against the background of existing power structures.

The four final theses take the path from analysis to the formulation of concrete ideas and proposals on how urban planning could respond to the various challenges of the single-family home. They are not utopias written for the drawer, but what Marcuse calls realistic ideas for a ‘strongly hoped-for future’.

The first article by Janina Hain explores the extent to which the planning culture of local actors characterises the development of new single-family homes at municipal level. Laura Fritsche analyses the range of formal and informal planning approaches used by municipalities to gain more control over single-family housing estates and shows that the instruments are not only quite limited, but also not fully utilised. Cora Sauré sheds light on how the instrument of integrated urban development planning failed in the context of an ageing single-family housing estate due to private owner interests, among other things. Finally, Madita Pyschik takes up the question of ownership further by analysing the possibilities of municipal acquisition of private property and non-private forms of housing using a scenario analysis.

Author: Michael Schwind

Although municipalities are increasingly deciding to restrict building possibilities, the trend of designating single-family homes on the outskirts seems to be unbroken (Bundesstiftung Baukultur, 2018, p. 20). While economic motivations for ongoing designations have already been researched in depth (e.g. Behnisch et al., 2018), we often do not yet sufficiently understand the influence of local maxims for action and individual planning values. Planning culture research builds on this and understands spatial planning as a cultural practice whose framework for action depends on individual behaviour, cultural structures and local contexts (Levin-Keitel, 2016, p. i). With the help of this theoretical approach, I pursued the goal of understanding the community-specific approaches and personal attitudes of the actors, which have so far been less investigated in research, and exploring their influence on the designation of new single-family homes. In an empirical study, I analysed a local community with 4000 inhabitants in Rheinland-Pfalz.

The analysis made it clear that the maxims of action of the actors for the new designation of single-family house areas depend on many different factors and differ according to their own position, professional backgrounds and individual experiences: it was shown that the interests and decision-making motives of the actors also depend subjectively on their organisational role and thus tend towards institutionalisation. Having grown up in the municipality, the mayor's interests in relation to the development of new single-family home neighbourhoods, for example, were particularly focused on the general well-being of the village. In contrast, the employees of the municipal administration tended to take an administrative perspective on the rezoning process. Their involvement was limited to the accompanying implementation of the legal requirements, without any significant independent proposals being made. The planning office, on the other hand, acted primarily out of economic interest when awarding the contract and therefore also only exerted a marginal influence on the development. At the same time, there was a lack of prior knowledge of urban planning within the municipal council and particularly in the administrative area of urban land-use planning. This led to a delegation of responsibilities, as a result of which none of those involved felt fully responsible for the new designation and there was little discussion about housing formats other than detached houses. The actors were therefore only prepared to a limited extent to reflect on their own responsibility and options for action in the redesignation process and the individual perceptions and evaluations were correspondingly institutionalised.

The results of my work outlined here point to the importance of cultural characteristics in the municipal planning process and make it clear that these have so far received too little attention in planning theory, but above all in planning practice discourses. In order to understand why detached houses are still being built, it is therefore not enough to focus solely on structural processes: different cultural and communal factors exist and influence decisions. It is thus also worth focussing on the individual and sometimes contradictory interests, wishes and housing ideas of local stakeholders.

Author: Janina Hain

To what extent can municipal policy and planning in growing cities strategically steer the transformation of single-family neighbourhoods? With this question in mind, I analysed the cities of Augsburg, Hamburg, Kassel and Würzburg as part of my master's thesis, which are representative of growing cities that are confronted with steadily increasing pressure to grow, a high demand for space and thus a tight housing and land market (BBSR, 2021, p. 18).

The analysis of the case studies showed that, against the backdrop of sustainable urban development, internal development is becoming increasingly relevant (BBSR, 2021, p. 18) and, in view of this, existing single-family home neighbourhoods are also increasingly becoming the focus of municipal policy and planning. However, this is not a specific urban development policy discourse; rather, the transformation of single-family home neighbourhoods is embedded in the overall urban goal of inner-city development. However, the existing single-family home neighbourhoods are not only being addressed due to the high land consumption, but also due to the homogeneous population structures, the ageing population, the below-average residential density or the low functional mix.

Municipalities have a range of formal and informal instruments at their disposal to deal with these various challenges and thus also with the transformation of single-family home neighbourhoods. While the formal instruments include, in particular, the possibilities of urban land-use planning with regard to changes or new development plans, the informal instruments and strategies include development concepts of all kinds, land management and monitoring as well as various forms of information, participation and consultation. The municipalities analysed use a mix of instruments and methods in order to make the best possible use of municipal control options (Wüstenrot Foundation, 2016, p. 240). Nevertheless, the municipalities' scope for action and influence is perceived as very limited. On the one hand, this is due to the ownership structure, as the transformation of single-family home neighbourhoods is largely dependent on the will of the owners. Secondly, the strategies and control options available are predominantly informal instruments that are not legally binding and are also considered to be complex processes.

Overall, it can be stated that the municipalities analysed are in a kind of self-discovery phase with regard to their own role in the transformation of single-family housing areas, which is accompanied by planning and political uncertainties (Wüstenrot, 2012, p. 292). According to their self-image, the municipalities take on different roles (ibid.): they can control structural changes and densification in single-family housing areas in a planning and regulatory capacity (ibid.), accompany the transformation of single-family housing areas as an observing and advisory body or take on an initiating and promoting role in order to encourage the implementation of municipal planning intentions (ibid.). While Kassel and Würzburg define themselves more through an observing and advisory role, in Augsburg and Eimsbüttel, on the other hand, there is already a need to intervene in a planning, regulating and initiating capacity due to the shortage of space. Municipalities are growing with their tasks and, in the long term, will have to deal with the transformation of single-family home neighbourhoods as growth pressure continues.

Author: Laura Fritsche

Once the residential ideal of West German families, single-family housing estates from the 1950s to 1970s have lost their appeal today. In times of climate change and housing shortages, making them fit for the future again is an obvious choice. To what extent does the instrument of integrated urban development offer a partial answer to these challenges?

Mostly located in suburban or rural areas, the settlements are characterised by functional and social homogeneity (ARL, 2018, p. 5) and have aged in two ways over the past decades - in terms of population structure and building fabric. Their future prospects depend on local parameters, in particular their location in growing or shrinking areas (Berndgen-Kaiser, 2012, p. 22). Integrated development concepts could take this into account appropriately, as fields of action are identified on the basis of analyses and individual development proposals are drawn up. However, the application of such concepts at the level of single-family housing estates has so far been the exception.

In the thesis, I addressed this application and research gap and posed the question of the framework conditions for revitalisation by means of a development concept. The old housing estate in a small Franconian town served as an example in the case analysis. Although a neighbourhood concept had been developed for it around ten years ago as part of a model project, it had never been implemented. Interviews with the building and urban development authorities, the concept authors and civil society, as well as local reporting, statistical data and photographic and map material, revealed a number of inhibiting factors, which are outlined below.

It became apparent that the staffing levels of the building authority in the small town analysed were already tied up with mandatory tasks. Additional actors and resources would be required for projects that go beyond this, such as the establishment of neighbourhood meetings and intergenerational neighbourhood networks. In addition, revitalisation measures can hardly be financed from the municipal budget, so the barrier-free redesign of street spaces, for example, takes decades. As the municipality does not have access to private properties, it is dependent on the cooperation of the owners, for example, when it comes to the subsequent creation of age-appropriate housing in the neighbourhood. Greater involvement on the part of residents seems reasonable in view of the indirect enhancement of their private property in the course of revitalisation. However, reaching and sensitising senior citizens and young families alike in low-threshold participation formats and releasing their capacities for involvement remains a challenge.

The example of the Alte Siedlung shows that revitalisation cannot take place without an activated civil society, the political will and long-term planning support, such as neighbourhood management. The financial support of development concepts and concrete measures is a decisive factor. This would allow pilot projects to be implemented and valuable experience to be gathered on how the potential in ageing single-family housing estates can be realized.

Author: Cora Sauré

As has already been shown in the previous articles, in addition to the question of the extent to which the construction of new single-family homes can be justified in the future, it is equally relevant to look at the existing housing stock. How could this be further developed in order to respond to the criticised continuation of homogeneity and monofunctionality as well as their ecological effects? At least for some of the housing estates, new perspectives could be offered in which they could become denser and more diverse in terms of their residents and uses.

In my thesis, I considered the characteristic feature of home ownership as a possible factor for implementing changes in three scenarios. Until now, the single-family home and private home ownership have traditionally been seen as an inseparable unit - summarised under the term ‘owner-occupied home’. Currently, around 88% of single-family homes are privately owned (BSBK, 2019, p. 59). Public welfare-oriented actors and the instruments available to them were subsequently considered as potential supplementary ownership structures. Their aim is to remove housing from the value increases of the free market and thus guarantee its affordability in the long term (Balmer & Bernet, 2017).

For comparison purposes, Scenario 1 initially described the continuation of the typical sales and acquisition processes between private households, while Scenarios 2 and 3 describe the emergence of new players. In these scenarios, the focus was on the extent to which existing land and buildings could be transferred to non-private and public welfare-orientated forms of ownership. Although the unity of land and building is maintained in scenario 2, ownership is taken over by a cooperative housing project. In scenario 3, with the support of other actors - land foundation or municipality - this association can finally be broken up by applying the instrument of heritable building rights.

The specific selection of additional forms of ownership was made on the basis of the framework conditions of the specific case study - a neighbourhood in a suburban district of a major western German city. The case study serves as a proxy for comparable single-family home neighbourhoods; however, a direct transfer of the results is not possible due to the respective local conditions.

In the formulation of the scenarios for this context, however, the answer to the question posed at the beginning as to whether existing single-family housing estates could be further developed with regard to the ‘home ownership’ factor is: Yes! A spectrum of ownership structures would have a particularly positive impact on the socio-spatial design, as other forms of housing and household sizes could be accommodated away from the traditional nuclear family.

However, even in the case of changes of ownership, which I consider to be realistic starting points for change due to the high reputation of private property, financial and structural starting points in particular pose ongoing challenges. In particular, due to the fact that they are embedded in a property market that remains profit-oriented, actors willing to implement change would initially need a high proportion of equity capital to pay the current market value for the owner-occupied homes before they could be transferred to a use oriented towards the common good. Without concessions from the previous owners or support from other stakeholders, especially the municipality, this does not seem feasible. In addition, the isolated sales processes mean that only small-scale projects can be realised. The houses and plots of land that were previously tailored to one household would also have to be structurally adapted to the needs of other housing constellations, which is often only possible to a limited extent (depending on the applicable building law). Depending on the age of the buildings, modernisation and refurbishment may also be necessary. With regard to these challenges, it seems unlikely so far that public welfare-oriented actors will ‘venture’ into the single-family home neighbourhood category and thus change it.

However, as additional ownership constellations can have a positive impact on the design of single-family home neighbourhoods, consideration should be given to how to meet these challenges.
On the one hand, the municipality appears to have a key role to play in supporting civil society actors. On the other hand, however, financial support for property ownership should not only be tailored primarily to owner-occupied homes, but should also favour the acquisition of other forms of property.

Author: Madita Pyschik

From a theoretical perspective, the works ask about the specific challenges in the reorientation of dealing with single-family house areas and single-family houses. Which (new) actors come into question? Which existing or new strategies and instruments can be used to remodel single-family housing estates, for example through redensification? And how can new ownership structures be implemented in single-family home neighbourhoods?

The studies on planning cultures and the use of instruments and strategies in dealing with new detached house areas show that, contrary to all professional arguments, the ideal of a home with a garden is still firmly anchored in society and that alternatives to this form of housing seem unthinkable in some places. Apparent bans in the form of non-designation cause a reaction and thus continue to hinder exchange, but can no longer be avoided in view of the shortage of space. They should be accompanied by a broad discourse on the criteria of ‘good’ housing and the creation of attractive alternatives to home ownership. Be it privacy, the form of ownership or the location - the advantages of living in a detached house can also be achieved in a similar way in other types of housing.

An important factor in considering how to deal with the stock of detached houses is the involvement of the owners. The protection of their property and their property rights is given higher priority than the obligations to the general public that go hand in hand with home ownership. Under current legislation, owners do not have to bow to top-down criticism of single-family housing estates and their development prospects. Rather, it is the task of urban planning to sensitise and motivate the private owners of single-family homes to support the goals of public welfare-oriented planning and not only to support the resulting measures, but to actively help develop them. However, such a coordinated and participatory approach requires resources both on the part of urban planning and on the part of the owners, which are often not available in reality. It is therefore important to prepare planners for dealing with residential areas with small-scale ownership structures, to further develop formal and informal instruments and to create suitable funding programmes for their implementation.

Authors: Johanna Günzel, Michael Schwind, Sandra Huning