Agriculture as a Catalyst for New Forms of Urban Habitat in Residential Architecture. A Case of Multi-Family and Mixed Housing Estates from 2010–2021 – European, American and Asian Context

In this paper, it was decided to examine the issue of designing a particular type of multifunctional objects, combining in one form the architectural function underlying architecture as such and one of the latest urban functional “discoveries”. A combination of a multi-family housing function with urban agriculture and additionally – with service and commercial elements became the key point of the analysis.

Currently, the structure of residences and the appearance of cities, especially in the most urbanized areas, are changing dynamically. Successive crises of the last dozen or so years have shown that most cities are defenceless in the face of unexpected situations, especially in terms of the need to provide their inhabitants with fresh food. The necessity to combine housing and agriculture should therefore be slowly treated as a close relationship. It is only important to diagnose what stage of this development we are currently dealing with and whether these functions will be more and more closely related to each other, or whether they will function side by side, but independently so far.

Certain conclusions on this subject can already be drawn on the basis of the analysis of the connections between residential buildings and greenery, implemented in accordance with the assumptions of sustainable development in an increasingly close relationship with it over the last ten years. Solutions of this type may become a model for shaping residential and agricultural buildings in the future.

The above-mentioned comparative analysis of global samples referring to the location in the regions from which the examples of the second part of the analysis of agriculture-related development, allowed to define a number of solutions related to the introduction of greenery in conjunction with the typology of multi-family housing development. The most common type of solution is the introduction of greenery in the form of permanent pots serving as part or as balustrades of balconies or terraces themselves, constituting a part of the external private space of apartments. In the case of buildings other than residential tower blocks, a typical solution is the use of green terraces, often as a common space in buildings, green roofs, and depending on the location of the building in relation to directions of the world – also green walls. Paradoxically, when greenery becomes an integral part of the architecture, home gardens at ground level cease to be used as one of the solutions.

At the same time, the emergence of solutions linking the agricultural function with public, administrative and office facilities for higher-level services has resulted in creating a new canon of spatial solutions and an aesthetic canon which is now being reproduced in case of linking agriculture with the residential function. Currently, buildings such as the Pasona Urban Farm in Tokyo or the ICTA-ICP experimental office and laboratory building in Cerdanyola are consolidating the new type of solution patterns used [1, 2].

Nowadays there is a tendency to create multifunctional facilities based on the residential function by replicating the canon of solutions marked for the recreational greenery. Familiar solutions are repeated especially in the case of the educational and informational role of residential agriculture. In the case of green areas which are to play a nutritional role this pattern is developed further. The emergence of estate greenhouses, linked to varying degrees to dwellings themselves or to the estate as a whole, shows that urban agriculture is becoming a catalyst for the emergence of new spatial forms, hitherto unheard of apart from certain functions perceived as experimental.

In the carried out research, a number of theses related to the reason and form of the introduction of farming greenery as an element of newly created urban multi-family residential architecture were put forward.

The introduction of farming greenery into apartments’ interiors and linking housing with agriculture was possible as a consequence of a closer connection between architecture and green, and the implementation of sustainable design principles on a larger scale. A more complete integration of functions was possible by creating a canon of forms and the scale of this connection. Certain patterns of solutions have become relatively easy to combine due to their convergence with elements that have already become a part of residential architecture. The combination of housing and agriculture should therefore be slowly treated as a close relationship, where the farming is fully dependent on the housing part and replaces certain elements of complementary functions at the same time. Simultaneously, the adopted direction of development goes towards total dependence between functions, i.e. programmed self-sufficiency causes the residential function to lose its sense without agriculture and vice-versa.

Based on the analysis of the above-mentioned examples, a thesis was also put forward about the possibility of integrating functions in buildings with a compact layout, in which the preferred type of shaping the internal structure of flats is scheduled and mesonet flats, while the introduction of an integrated agricultural function did not extend the typology of flats in multi-family housing. The new type of architecture changed the way the flat plan was shaped in terms of planning its day zone, linking it with the cultivated area of buildings.

An intensive search for new housing solutions to bring nature closer to the city accelerated rapidly from the beginning of 2020 as a result of the Cov-19 pandemic and attempts to prepare for similar situations, resulting in the necessary programmatic increase in the self-sufficiency of urban housing and an increased concern for self-sufficiency and maintaining a relationship with nature in the operation of individual facilities.

As a result, a new type not so much of dwelling but of housing has developed, in which the agricultural function replaces, in part, that of social services, recreational areas and estate greenery.

Agriculture integrated with architectural structures has been a topic of research since the early 2000s, when there was actually a clarification of the subject from earlier conceptual and theoretical explorations. It is now accepted that the most promising direction is the creation of highly efficient hydroponic structures, based on renewable energy sources generated on-site, similarly extracting the water necessary for plant growth recovered in a closed loop from the functions that agriculture accompanies [3]. Other, less strict forms of linking urban residential development with agriculture are analysed, including various types of cooperatives ranging from community gardens to urban farms using land-use features [4] in an attempt to create a healthy urban living environment [5].

The most technologically advanced research currently conducted is concerned with the search for exemplary technical and spatial solutions in the experimental environment. The most recognizable example at present is the ICTA-ICP research building at the campus of Universitat Autònoma de Barcelona in Cerdanyola, by DATAAE and HARQUITECTES [6], where a complex of 4 iRTG greenhouses with their engine rooms was located on the top floor [7], directly accessible from general communication. Further research on the technology used in the building in the context of air recirculation and potential biological pollutants proves the possibility of even further functional integration of facilities and creating a form of closed systems [6, 8, 9].

Current trends in the form of buildings themselves and the way they are internally organised have been very much influenced by the realisation of a building with a non-residential but office function, combined with plant cultivation in an enclosed environment. The Pasona Urban Farm headquarters located in Tokyo, which is actually a conversion of an existing office building, was designed by Yoshimi Kono and Yi-han Cao of Kono Designs. In this case, the cultivated vegetation is both an element of the site's identification system, consciously raising the prestige of the place, but also an element that constructs the space and influences the microclimate of the different functional zones [10].

Simultaneously with the latest research in this field, conducted mainly in terms of the applicable technologies of urban closed crops and their relationship with the form itself, but above all with the way the buildings thus produced function, it is important to search for historical foundations and concepts that affect the shape of solutions, currently proposed as an element of tradition and culture.

Of the analyzed facilities, only one has already been described in the literature, but only in terms of its role as an example of circular architecture [11]. According to the analysis of H. Ping Tserng, Cheng-Mo Chou and Yun-Tsui Chang, the agricultural function in Taisugar Circular Village is an element of the circular economy strategy in the field of landscape architecture, implementing two of the 5R postulates – think and limit [12, 13].

Concept designs were ahead of the appearance of the first implementation projects by some 2 years and then developed in parallel with them. The most famous of them, including those selected for this analysis, were created for the needs of various architectural exhibitions and festivals, including the Venice Architecture Biennale and the World Architecture Festival. Thus, they constitute in principle a radicalised, total version of the assumptions that must be adapted at a later stage to the parameters of the real environment and its constraints. They are intended to highlight certain current socio-cultural problems that contemporary architecture will have to deal with. Hence, giving additional purposefulness to the designed residential buildings reaches to the problems of the revitalization of high-rise buildings and attempts to search for their new functionality that will work in specific conditions (i.e. Self-Sufficient Skyscraper by Terreform), or the problem of rapid ageing of the population in developed countries (i.e. Home Farm by SPARK), combined with the already well-known and described problem of the nutritional self-sufficiency of cities and the reduction of the carbon footprint of food production and its transport from outside of urban areas.

The analyzed solutions concern high-rise buildings and skyscrapers. They assume an extremely radical change in the approach to the way of contemporary living, analyzed on an urban scale, as well as the adopted functional program and the method of its implementation. Facilities assuming full self-sufficiency have a relatively small living space in relation to the area of indoor farming. Functions are related to each other in a way that could be called traditional – without full integration, the linkage occurs through limited internal communication paths, vertically or horizontally. An important feature of the discussed solutions is the fact that they are the most comprehensive ones, and therefore also the largest in terms of both the usable floor area of apartments and their number, as well as the cultivated area in total. In the extreme case of the oldest concept under discussion (Self-Sufficient Skyscraper), over 58.5% of the agricultural area was assumed in relation to the general utility function (excluding the area of built-in parking lots). As the idea developed, the more realistic concepts were, the more this proportion shifted towards reducing the actual size of farming areas in favour of services and parking areas.

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In the case of concept designs, intended ultimately for implementation, i.e. resulting from commercial orders, such as Secret Gardens or Taisugar Circular Village, there is a much greater impact of actual market requirements, determining both the size of the investment itself and its internal structure. The proposed architecture takes a more traditional form, referring both to the urban context of the place and generally – compact, traditional architectural forms used in the shaping of housing structures in the particular urban area. There are solutions that are more variable, both in terms of the structure and typology of multi-family housing and combining it with dense single-family housing (in most cases, terraced). Compact systems represent a mixed type of structure in the type of low-rise-high-density buildings. In this case, the building height does not exceed 7–8 residential storeys as an accent element, reaching the typical height of 2–3 storeys. In the case of these solutions, residential buildings are integrated to a much lesser extent with agriculture, which remains an element introduced somehow additionally into typical systems as roof greenhouses or even placed outside the outline of the residential part. The estate in Wudong, as the only one of the discussed group, has greenhouses integrated with the main body of the building, the location of which depends on the direction of the sun and allows access to farming parts directly from the general communication routes, ensuring the fullest contact between nature and residents.

Two distinctive trends in the proportion of the functional programme can also be observed. In the S* Park and Taisugar Circular Village estates, there is a clear tendency to increase the proportion of the residential function in relation to the complementary agricultural and service functions (both public and social services – within the estates). In the discussed cases, more than 90% of the total usable floor area are flats, while the proportions in the magnitude of the remaining functions are divided into two relatively equal parts. Additionally, the built-in underground car park is becoming an important size in the shaping of the housing estates’ functional programmes.

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In the second group of estates emerging at the same time, there is an even more pronounced tendency to marginalise agricultural and service functions. In this case, the amount of cultivated land in the total usable floor area does not exceed 1%, which makes it difficult to see the declared emergence of urban agriculture in developments such as Secret Gardens and Grow Community as a real change in the way urban housing is designed. This is particularly evident if one compares these volumes to the analogical ones in the theoretical projects, in which the (even merely declarative and therefore probably overestimated) efficiency of urban farming was taken into account in shaping the functional programme, and on this basis, the necessary area of cultivation for at least minimal food self-sufficiency of the settlement was determined.

This last trend also includes the only Polish example of this type of housing estate so far. The Evergreen 365 estate in Poznań is characteristic in that it offers a new type of solution for the external space of the apartment, as a combination of balconies and greenhouses, the development of which was left to the owners. Hence, it cannot be unequivocally assumed that all of them will actually fulfil a farming function, especially since they do not have, apart from the greenhouse structure itself, any technical facilities dedicated to cultivation.

In the case of the multifamily developments themselves, it is difficult to distinguish one dominant systematic pattern in the analysed examples. In the case of conceptual solutions, it is relatively common to find point solutions, which are not found in the case of developments to be built. The latter type is in fact dominated by multi-point, line or poly-line shape typologies. Equally frequent is the gallery layout, which is rarely used in the most recent residential developments with a standard utility programme. This is due to a characteristic feature of floor plans with galleries, the layout of which is clearly dictated by the sun exposure, which results in the galleries being located on the north side (for northern hemisphere locations) and the day parts of the flats on the south side for better overall sun exposure. Hence the popularity of this layout for developments with features such as urban indoor agriculture and solar power plants (location with southern exposure).

The size of the designed apartments is very variable, depending on local preferences, and ranges from 25 to over 215 sqm. There is a clear difference between the size of flats in conceptual projects, designed for a programmed group of users, and solutions intended for commercial sale, where typical market parameters were taken into account, such as the average size of a household, location (urban-suburban areas) and the credit capacity of future residents. In the first group, this value ranges from an average of 65.03 to 100.5 sqm of usable floor area, while in the case of implemented designs, the difference in average values is much greater and ranges from 36.5 to 131.98 sqm. Despite such large discrepancies, the average size of a flat in both cases fluctuates around 85 sqm.

The number of apartments in the complex ranges from 51 to 351 in the case of the Home Farm housing estate. Although the difference is significant, most of the examples do not exceed the size limit of 120 apartments, and the average for the analyzed examples is 153, which meets the requirement of the size of a neighbourhood development complex – a habitat in which everyone will know each other by sight [23]. This is an important element for shaping the estate as a community centred around the characteristic element of intra-estate farming.

In the method of forming the internal layout of the apartments, there are no clear differences between the solutions currently used in so-called standard development. Scheduled flats or, in the case of the largest ones, corridor flats are the preferred layout. A characteristic feature is the lack of the preserved zoning layout of flats and their – it would seem – program resembling typical solutions. In the solutions of internal systems, however, great importance was paid in each case to the close relationship between the apartment and its surroundings. The private external space of the apartment is extended and expanded with parts related to greenery, but only in the case of the Evergreen365 estate it can programmatically fulfil the function of cultivation by introducing greenhouses on balconies directly belonging to the apartments.

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Built in 2013–2016, the Evergreen 365 estate at Grochowska Street in Poznań is the first national example of an attempt to expand the functional program of a housing estate with elements related to a private outdoor recreation area, which also allows, though not imposed by the program, small-scale horticulture. Developed by the architects: Szymon Januszewski, Piotr Napierała and Marta Łykowska from the Insomia architectural studio, it first of all, shows an unusual form of the facade. The complex of two buildings in multi-point and line shape typology was connected with an underground build-in car park and an extensive service ground floor. On the south and east side, constituting the internal courtyard of the complex, there are extensive balconies belonging to each of the apartments. On each of them, on the south facade, there are a total of 21 greenhouses with an area of approx. 4 sqm each. Creating the archetypal form of a greenhouse – cubes with a gable roof, the authors referred to the idea of creating a “substitute for a single-family house” [24] in the city. The number of designed apartments (51) and their size (from 41.5 to 93 sqm), as stated by the authors themselves, was not the result of design calculations, but the implementation of the maximum possible number of apartments and the decision made by the client, whose original intention was to sell small, 1 and 2-bedroom apartments, and the completed facility was a risk incurred in order to increase the possible sales area [20]. However, not too lofty goals made it possible to achieve a valuable space, as they caused a significant change in the profile of the estate's inhabitants towards family solutions.

In the case of multi-family housing, the emergence of agricultural greenery changed the way the greenery itself was integrated with architecture. At the same time, forms of its occurrence have also changed. While in the case of traditional greenery in the analysed examples it was most often in the form of permanent, large-scale pots integrated with external balustrades, green roofs and terraces, but also, although slightly less often – as green walls, in the case of introducing agricultural greenery, these were not so popular. In the case of housing estate agriculture, it usually took the form of a backyard, individual gardens in the ground floor area or roof greenery, but primarily as greenhouses located in various places on a plot or integrated with the building structure. This form appeared also in the case of traditional greenery, but it was a marginal element, not as popular as in the case of urban agriculture, where it was present in all cases. The new form of multi-family and mixed-use urban housing is already creating its own catalogue of spatial solutions linking this specific type of greenery with architecture in an even more durable way. In this case, greenery becomes an integral part of the building, more and more independent of external conditions.

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Basically, it is possible to make a statement about the emergence of a specific spatial form of an estate, in which the new function takes its own, characteristic form, while the original – residential one remains unchanged for the time being. The fullest integration of functions takes place in the analysed examples thanks to using elements of the already created canon of forms and the scale of these settlements. A characteristic feature of the created space is its compactness and relatively high density with the simultaneous solidity of the complexes.

The conceptual designs take a more organic form, confining themselves to more unusual, schematic forms of introducing farming as a representation of innovative solutions – green walls and crops occupying non-characteristic, intermediate floors of buildings. Objects implemented or intended for implementation show much more common features in this respect, duplicating solutions typical for those used nowadays. The introduction of an agricultural function is in each case associated with its functional classification into specific functional groups – recreational, service or community – and their appropriate shaping within the development complex. In this case, the element of reducing energy demand is also taken into account, through the location from the south – preferably sunny or least shaded, as well as the use of the top floors of buildings. Therefore, the architecture of urban housing estates takes an additive form, where the agricultural element is added or extended to the currently typical form of a modern ecological housing estate, with a relatively high intensity of development while maintaining its limited height.

Contrary to initial expectations, it was not possible to define the preferred type of housing used in the event of a combination of multi-family housing and agriculture. In the analysed estates there are all, apart from the circular ones, functional layouts of flats, regardless of the functional connection and solutions applied in the field of urban agriculture. The introduction of the integrated agricultural function did not extend the typology of apartments in multi-family housing. Typical solutions are adopted, depending only on the local preferences of potential buyers. The greatest change in this respect was, paradoxically, suggested by the example of Poznań's Evergreen 365, and from a historical perspective – by Le Corbusier's proposal in Immeubles Villas. The new type of architecture did not fundamentally change the way of shaping the floor plan.

The morphological analysis of the discussed examples shows two main trends recurring both in the case of theoretical and implementation solutions. The first one assumes the selection of a location as a complement to the existing, compact urban structure. In this case, the choice is made on areas located inside, well-shaped, compact downtown structures and adapting the form of complexes to the surrounding buildings. In this case, the role that unites and integrates the forms becomes important, in which the new element becomes the keystone, a clear accent of the entire system. Much fewer examples are located in the area of newly formed districts or larger building complexes, so that at the time of construction they do not yet have the context of a close neighbourhood. The lack of surrounding buildings means that it is the new form that has all the predispositions to give direction to further development in a given area, constituting a reference point for future designers. Therefore, it is an interesting direction of research in the future, allowing to assess the impact of the new function and its spatial expression on the surrounding buildings in the context of its potential centre-forming role.

However, the fact that the intensive search for new housing solutions in order to bring nature closer to people in the city resulted from the Cov-19 pandemic, and their unflagging popularity proves the growing need for broadly understood ecological self-sufficiency implemented in the immediate vicinity of the place of residence cannot be underestimated.