Written by Vincent Le Rouzic, director of studies at La Fabrique de la Cité, this new note highlights the difficulty of reconciling the objective of soil preservation, the needs for housing production and the aspirations of a majority of French people to live in individual housing.
It offers possible solutions to meet the objective of land sobriety. A large majority of French people would approve of measures to renovate the existing housing stock despite the difficulties that such a project represents. In addition, soft densification initiatives are progressing in certain territories.
For Vincent Le Rouzic: “Contrary to certain preconceived ideas, a large majority of French people favor 'tiny gardens', i.e. gardens of less than 500 m². Yet in 2021, the average land size for building new detached houses was still 947 m². Reducing the size of gardens in new individual housing projects would therefore open up prospects for reinventing the individual house at a time of the fight against the artificialization of soils. »
This publication is the third note from the project launched by La Fabrique de la Cité on the objective of Net Zero Artificialisation (ZAN).
This subject of study will continue in 2023.
Will the year 2022 have been a historic turning point for the sector of French individual houses? Probably yes. The legal liquidation of Geoxia, the builder of the emblematic Phoenix house, is certainly the major event symbolizing the sudden reversal of this market. At the same time, the objective of zero net artificialisation of soils (ZAN) is sowing discord. The new regulatory provisions resulting from the Climate and Resilience law come to impact the imagination of the pavilion with garden, also considered as an artificial surface. Therefore, what is the range of possibilities for individual houses at a time of the fight against the artificialization of soils?
The individual house, the first source of soil artificialization
The question of the future of the single-family house is probably one of the most controversial for implementing the ZAN objective. If housing policies have been the subject of continuity for decades, despite government alternations (Worms, 2016), it is finally the choice of a change of model that Emmanuelle Wargon has acted, then Minister of Housing, at the conclusion of the "Living in the France of tomorrow" initiative in October 2021. She declared that "the old-fashioned model of a pavilion with a garden that you can walk around leads us to a dead end . This position was not new to the Minister, but the tone of the speech had an important media echo, taking a polemical turn a few months before the 2022 presidential election. Reconciling ecological, economic and social issues constitutes a way of ridge which can quickly become a way of the cross.
However, far from the caricatures reducing her discourse to "the individual house is an ecological nonsense", Emmanuelle Wargon first tried to outline a diagnosis by returning to the original sources of the "at the same time", adapting in an original way the presidential score in the field of housing: “Housing has a strong ecological impact for its carbon emissions, but also for the land it consumes and the transport needs it generates. And yet, housing needs are significant. They're not giving up, I'm thinking of all those badly housed French people, they can't be an adjustment variable. Concerning the single problem of soil artificialization, it is true that housing is the primary source of soil artificialization in recent decades. According to a study by CEREMA, between 2009 and 2019, habitat represents 68% of new artificialized land (Bocquet, 2020). In this set the individual house takes a very important part: for example, an INSEE study shows that between 2005 and 2013, approximately 90% of new artificialized land for residential use takes the form of individual housing (Albizzati et al., 2017).
 Closing speech by Emmanuelle Wargon, October 14, 2021, for the conclusions of the “Living in the France of tomorrow: reconciling opposites” approach: https://www.youtube.com/watch?v=ZxTlBHq3Dvo
To understand these results, it should be remembered that land take includes the entire plot on which a construction is built (including the garden for a detached house). The integration of garden areas in the regulatory accounting for land take has been retained by the government (see box). Two main reasons can justify this arbitration:
- from the point of view of planning policies, this decision constitutes a powerful lever for densification: for example, the plot of a house with a large garden can be divided up to allow new housing to be built.
- from the point of view of environmental impact, all or part of the three soil functions retained in the Climate and Resilience law near buildings are generally affected by human development.
 Article 192 of the Climate and Resilience Law retains the biological, water and climatic functions, and the agronomic potential.
French people divided between the desire for an individual house and soil protection
La Fabrique de la Cité commissioned an opinion poll from the Kantar Public Institute on the perception of soil artificialisation . The results show that the fight against land take is an important subject for 88% of French people. A large majority of French people (59%) consider the subject to be a priority. However, the French remain attached to single-family homes: according to the same survey, 79% would ideally prefer to live in this type of accommodation, a constant for several decades (around 75% to 80%).
These results show the expression of seemingly contradictory aspirations, so difficult is it to reconcile the fight against the artificialization of soils with the plebiscite of the ideal of the individual house. Does this mean that some French people would aspire to reconcile single-family homes and land sobriety? In any case, it is this middle way that we will now seek to explore.
 The Kantar Public institute carried out in June 2022, for La Fabrique de la Cité, an online quantitative survey based on a global sample of 1 interviews representative of the French population. https://www.lafabriquedelacite.com/wp-content/uploads/400/2022/Etude-complete10CF70_Fabrique-de-la-cite-LesFrancais-et-les-villes-moyennes_24.pdf
What room for maneuver to reconcile individual housing and land sobriety?
Focus on the existing stock and soft densification?
According to the survey carried out by Kantar Public, most French people are aware of certain measures to be taken to fight against the artificialization of soils. A very large majority is in favor of encouraging renovation and moving into old homes (78%).
In addition, initiatives seek to update various forms of soft densification of individual houses with large gardens. This is the case, for example, with the experimentation with the BIMBY (“Build in my backyard”) approach aimed at supporting owner-occupiers to build a new home in their garden. This approach has been tested with relative success in Périgueux, on the territory of the Creusot-Montceau agglomeration or the Territorial Coherence Schemes (SCoT) of the Central Vosges and Grand Nevers.
Towards a plebiscite of the tiny garden?
Considering that the fight against the artificialization of soils is important is not ipso facto contradictory with the ideal of the individual house. It all depends on which house it is and in particular on its qualitative and quantitative impact on the soil, placing the garden at the heart of the reflection.
According to the latest available data (Gadet, 2022), the average size of land for building new individual houses was 947 m² in 2021. However, according to the Kantar Public survey, ideally, it is sufficient to 37% of French people have a small garden (less than 250 m²), and 34% of them have a medium-sized garden (250 to 500 m²). Only 12% of French people say they want a large garden (500 to 1.000 m²) and 8% a very large garden (more than 1.000 m²). There would therefore be a gap between the aspirations of the French and the classic products offered by professionals in the construction of individual houses.
On a qualitative level, a literature review carried out by Flégeau (2020) on the link between urban forms and biodiversity reveals the many gaps and inaccuracies in the scientific literature devoted to this subject. In the current state of the scientific literature (Flégeau, 2020), it is not possible to establish a systemic link between the size of gardens and biodiversity: on the one hand, studies such as that of R. Smith and his colleagues -authors (2006) on the agglomeration of Sheffield, in the United Kingdom, showed that large gardens could accommodate more trees taller than two meters, vegetable gardens and composting sites; on the other, studies suggest that the most important criterion is not the size, but the management of the plot (Flégeau, 2020). Regarding the carbon storage of family gardens, it depends on many parameters. However, according to INRAE (2020), the conversion of agricultural soils into home gardens can result in an increase in carbon stocks, due to generally significant organic inputs.
Towards a continuum between individual and collective housing?
The classic distinction between individual housing and collective housing can also be revisited by considering it no longer as an opposition but as a continuum. There are indeed many forms of intermediate housing, whether it be more or less horizontal co-ownerships, the various forms of participatory housing offering "living together at home", or even small collectives offering generous private outdoor spaces. These solutions can contribute to meeting the challenges of combating the artificialization of land acceptable to the French.
Indeed, the Kantar Public survey identifies three main levers for the acceptance of collective living among those who prefer individual housing: (1) not being bothered by the neighborhood (32%), (2) having access to a private outdoor space (24%) and (3) save heating or energy (19%). If the last lever could progress in the context of the current energy crisis, the other two levers primarily concern the architectural quality of the housing on offer. In this perspective, the various initiatives taken by the government to put the issue of the quality of housing on the political agenda are consistent. And examples exist to operationally translate individual urban forms compatible with soil protection objectives.
 We can cite the Lemas Report on the quality of social housing of January 2021, the Girometti-Leclercq Report of September 2021 on the reference system on the quality of housing, prefiguring the launch of the program “Engaged for the quality of housing of tomorrow » supported jointly by the Ministry of Culture and the Minister in charge of Housing.
Find the full note here.