Digital Models for Technological Design of Social Housing Sustainable Renewal. a Selection of Case Studies on the First Public Housing Plan Stock in Rome (1964)

Carlo Vannini

According to the New European Bauhaus, a key area for a sustainable transformation of the built environment is the definition of new strategies and operational tools for the renovation of the existing building stock. It is therefore necessary to create environmentally sustainable buildings, reducing consumption and costs for the end user. The research^[1] focuses on how to renovate post-war social housing neighborhoods—not only in technical and energy-saving terms but also from a social, cultural, and economic perspective. The objective of this proposal is to develop strategies for the rehabilitation of a large stock of social housing projects in Rome which were realized between the sixties and the eighties of last century. The need to have strategies in place for the re-calibration of these buildings rather than their demolition is an important objective of the European New Green Deal. The research examines the predisposition to the implementation of improvement measures. The element at play here is digitization and the use of digital technologies for greater efficiency and sustainability, with positive spin-offs for the entire economy. This should re-qualify and enrich rather than demolish, resulting in a higher quality of space to support an architecture that meets the needs of the users. These solutions are not limited to technical-normative and typological-functional adaptations. They also consider urban, social and economic implications, as well as the design possibilities and explorations of this reinterpretation and recalibration in function of different contemporary lifestyles and societal needs, through the use of digital technologies.

1. Premise/Introduction

Historically, social housing has been a central element in the evolution of European cities: its affirmation since the end of the 19th century, in parallel with the improvement of housing conditions for the working classes, coincided with the affirmation of a high level of architectural and urban quality, contributing decisively to the development of national and transnational architectural currents and movements. This project looks at the possibilities for renovation of the modern building stock, which represents a major challenge for the future of the building industry, in line with the objectives of the European New Green Deal for revitalizing the economy and sustainable development (Bason et al., 2021).

Figure 1.Torrevecchia, the blocks facing the courtyard.

Credits: Carlo Vannini, 2022.

After the second post-war period, social housing became a key instrument of urban development in the suburbs, providing the general infrastructure of the territory. The Italian experience is part of this dynamic, and the example of Rome is particularly important. Its production of public buildings, made up of large interventions in terms of number and quality, represents 12% of the total urbanized area (Laboratorio Città Pubblica, 2009). The research proposes a reading of the built environment to explore its characteristics in terms of predisposition to undergo improvement interventions. The intention is to define strategies for the rehabilitation of Rome’s public housing stock (Bianchi & Paris, 2018), which was built between the 1970s and 1980s with a logic of maximum savings and which today shows various elements of fragility in terms of building consistency, architectural image and types.

2. The First Public Housing Stock in Rome

In Rome in particular, the approval of the 1st P.E.E.P. (Public Housing Plan) in 1964 inaugurated the period of the great dimension (Insolera, 2011). Inspired by international architectural trends - the Japanese metabolic projects, the English megastructural proposals, the French grands ensembles, etc. - new neighborhoods responded to the logic of self-referentiality and uniqueness of the architectural sign capable of becoming urban. Formal research, which also responds to more general changes affecting the logics of urbanization, is not the only motivation for this move towards the large dimension. In particular, the need to build a large number of dwellings in a short period of time is a result of the strong urbanization processes and the social and political dynamics that they generate. The size and the high concentration of cubages in unitary buildings allowed a significant reduction in construction time and costs, making the best use of urbanization networks (Cellamare, 2016). In this way a city of prefabricated parts, finished in itself, antithetical to the historical compact city was born.

The interest in this particular public housing project comes from the morphological and density characteristics that can differentiate the interventions from the conventional city, as well as the location of the neighborhoods, due to their contribution to the urbanization of today’s suburbs.

The peculiarity of this architectural heritage lies in the constructional, morphological and typological characteristics that are repeated according to the principle of industrial prefabrication, which lends itself to the approach of rationalization. With this in mind, there is a growing interest in the concept of digitization within building systems, as all areas of design can benefit from the potential of digital technologies for greater efficiency and sustainability, with positive spin-offs for the economy as a whole (Agostinelli & Ruperto, 2020).

Figure 2.First public housing plan stock in Rome (I° P.E.E.P.).

Credits: Municipality of Rome, 1964.

In terms of typologies, the research and experiments carried out within the 1st P.E.E.P. were significant and gave rise to avant-garde solutions (Maldonado, 1978). First of all, the large scale stimulated designers to break the traditional, schematic and repetitive aggregation between the different housing modules. The main objective was to provide a varied offer of different sizes and shapes of dwellings through the aggregation, in plan and elevation, of different residential and typological modules. Another experimental element was the morphological and functional organization of the spaces on the ground floors and in the roofs, with articulated pathways and common spaces, open and closed, clearly distinguishable in the overall organism. The inclusion of non-residential services aimed at integrating the dwelling and its urban context, re-proposing the human scale in interventions of a monumental nature. Pathways - balconies, walkways, bridges, subways - and the volumes of common services became iconographic and characterizing elements of the projects, in some cases even becoming toponymic references (Lenci, 2006). However, these intentions were largely disregarded in the realizations: the large size became mainly a constraint, and only in a few cases was it translated into articulated solutions and significant typological experiments. For various reasons, including specific regulatory requirements, designers were forced to interpret the ‘large dimension’ with the blunt tools of traditional typology. Two approaches can be distinguished: on one hand, the typologically experimental, utopian cases of “megastructures”; on the other hand, the traditional typological re-propositions on a large scale, simply “large” buildings. “Large” was transformed from a conceptual resource into a field in which models introduced by national laws or regional regulations could be applied, producing a typological homologation of the concept of social housing and a continuous formal repetition (Rossi, 2012).

The 1st P.E.E.P. and the spread of large size coincided with the opening up of the construction industry to industrialized technologies in order to guarantee faster construction times, the mechanization of certain processes and the reduction of construction costs. In an attempt to bridge the gap with the industrialization of construction in other European countries, interest grew in the prefabrication of building elements and the industrialization of building sites. Innovative aspects such as the prefabrication of components and the rationalization of construction processes were well suited to the open morphology characteristic of interventions and the repetitiveness of work. For this reason, the majority of the Public Initiative interventions were oriented towards this construction model. Two fundamental innovations were used: standardized techniques for the casting of structures and industrialized techniques for the prefabrication of building elements (Lenci, 2009). The main innovations concerned the realization of the load-bearing structures and the construction of the envelope elements. The former made it possible to simplify and speed up the work thanks to the prefabricated and reusable formwork, as well as the simultaneous casting of the vertical and horizontal elements (inverted U formwork, coffer tunnel), guaranteeing a particularly rigid structure that has proved to be durable and efficient over the years. The latter, with prefabricated elements to be assembled on site (sandwich panels), has over time shown problems of durability and impermeability to atmospheric agents, especially at the interface with the structure. The introduction of prefabrication has led to a renewal of housing design at various scales, from the individual dwelling to the building and the neighborhood. The repetitiveness of the casting and assembly operations, as required, ensured the necessary reduction of the site’s incidence in terms of time and cost (Diana & Gissara, 2020). Overall, however, the repetitiveness and standardization of the final product was achieved. A direct link was established between the production factors and the typological conformation of the dwelling, which could also have many negative effects. For example: the internal longitudinal distribution was strongly influenced by the transversal load-bearing partitions realized through the use of prefabricated elements for casting; the repetitive sequence of prefabricated infill panels in the elevation increased the semantics of loculus and visual homologation. This contributed significantly to the discrediting of the use of systems such as the coffer tunnel and sandwich panels (Marcheggiani, 1977).

Figure 3.Quartaccio compartment R2, abacus of prefabricated façade panels.

Source: Central State Archive, Pietro Barucci Archive.

3. Best Practices Analysis: Case Studies of Contemporary Retrofit Projects in Europe and UK

Today, digitalization in the construction sector is synonymous with design and process management through the widest possible sharing of information in an electronic and organized form. Integration and collaboration are therefore opposed to the fragmented and competitive nature of traditional business methods. For the purposes of this project, the focus has been on European examples because of legislation, construction techniques and lifestyles. Many housing complexes built in the 1960s and 1970s in Europe have recently been renovated, demonstrating a growing awareness of an approach that values social housing as a lasting asset (Graf, 2014). The case studies were selected to:

be representative of a range of building types and environmental conditions across continental Europe and the UK
to provide a holistic perspective on the refurbishment process
to offer effective measures and to raise an exploration of architectural expressiveness.

A number of additional aspects were considered too. Firstly, the geography of the analysis is limited to those areas of Europe and the UK where the ageing of the building stock is more evident, where its transformation rather than demolition is more entrenched, and where decarbonization policies are more emphasized. Specific selection criteria were:

Functional: residential or predominantly residential;
Typology: apartment buildings;
Construction period: buildings originally built between World War II and the energy crisis of the 1970s;
Retrofit period: renovations completed in the 2000s.

These projects promote a reinterpretation of the built heritage in function of new ways of living and experiencing the city. They do not limit themselves to technical-normative and typological-functional adaptations, but also think about urban, social and economic implications. In line with European regeneration strategies, they have the capacity to increase integration and social inclusion, going beyond an exclusively environmental interpretation of the sustainability of interventions. These cases do not involve demolition, but rather the replacement and integration of new volumes, favoring light and dry construction technologies to optimize intervention times and exploit the full potential of an industrialized approach to execution (Lefebvre et al., 2022). These interventions are carried out economically and quickly, reducing social inconveniences and guaranteeing a high level of quality; sustainable materials and passive technological systems are favored. Particular attention is paid to the theme of contemporary living, reinterpreting existing typologies to meet an increasingly heterogeneous housing demand; the new project spaces envisage flexible functional areas with multiple uses, easily adaptable to the different lifestyles of their inhabitants over time.

4. Research Methods and Considerations

The research proposes to scale this approach up to residential buildings, investigating solutions that act on the architectural envelope, both in terms of controlling energy consumption and prolonging the useful life of these artifacts (Graf & Marino, 2016).

The operational methodology is organized in three activities:

The first one consists of the historical, design and urban analysis of the buildings belonging to the Public Agency for Social Housing of Rome, through research of the archives of the Agency and the architects involved in the design process. In parallel, a study and systematization of the most significant best practices of architectural and environmental retrofitting interventions are carried out to identify the parts, systems and building components involved.
The second activity is to create digital models of the buildings by digitizing the found material using parametric software (Tasselli & Maietti, 2021). Then, a diagnostic-cognitive^[2] evaluation of the artifacts will be carried out, in particular of the elements that are most affected by obsolescence and that could affect performance levels. This will highlight the challenges associated with changing housing needs.
The third phase consists in the elaboration of a set of specific components of industrial production and the creation of an abacus of parametric type solutions, constituting a digital library of experimental building components with tables of renovation costs.

The main elements of interest concerning the buildings of this period are:

The numerical consistencies and the locations of the districts, which make Rome a unique case for the number of housing units built and for the contribution made to the urbanization of today’s suburbs;
the morphological and typological features;
the construction characteristics, with prefabricated elements or tools aimed at the industrialization of construction processes.

These characteristics mean that such buildings lend themselves to a digitization process. Incorporating building knowledge throughout the construction process via digitization can greatly enhance energy efficiency in buildings (Cinquepalmi et al., 2023).. This can be achieved by integrating and optimizing all phases, from design and construction to management and control systems, using principles of Industry 4.0. Industry 4.0 involves the integration of information technologies in industrial production and the adoption of new methods of data management (Granda & Montaño Bello, 2021). By utilizing these technologies, manufacturers and the building process chain can improve efficiency, reduce waste and costs, and effectively meet user needs. The adoption of advanced technologies in the construction industry is crucial to save time, increase productivity, and respond flexibly and efficiently to industry demands. The transformation of monitored data into structured information supports decision-making in building management and operation, which is made possible through a mature process of digitization. Ultimately, the goal is to achieve greater energy efficiency and optimize the operation of buildings.

Figure 4.The Archive of the Studio Passarelli.

Credits: Carlo Vannini, 2019.

The aim of the study is to make clearly differentiated interventions coexist in order to restore a livable space with minimal financial resources, paying great attention to the duration of the construction site and thus the movement of residents made possible by having a single manager, such as the Social Housing Public Agency or the Municipality of Rome. Thanks to the study of the soft parts of the building, a digital catalog of solutions is defined and applied to the renovation of the existing building stock (Bologna, 2021). The answer lies in an integrated approach to the construction process, involving all stakeholders, with the aim of extending control over all phases of a building’s life, optimising energy resources and limiting environmental impact.

Re-qualifying, adding, enriching rather than demolishing can lead to a higher quality of space, supporting an architecture that meets the needs of users (Caruso, 2017). A message of responsibility and coherence with the requirements of a precarious economy trying to recover from the crisis, favoring the redevelopment of suburbs in a way that is not quantitative but qualitative; it is a contemporary approach, conscious and closely related to the conditions of current design.

In conclusion, the project begins by overcoming prejudices about repetition, recognizing the intrinsic value of the original construction considered in its entirety, and developing a new modality of intervention that will only be completed with the direct participation of the new inhabitants. Architecture can and must restore the dignity of the original construction of these artifacts (Claudi de Saint Mihiel, 2022). The strong potential of this project lies not only in the effects on the perceived quality of the urban space following these regenerative interventions (Plowright, 2022), but also in the theme of a memory that is preserved through regeneration rather than demolition.

5. Possible Impact of the Research

The results of this design experiment can form the basis for defining intervention models, with different declinations, within the composite heritage of social housing, proposing recurrent, possible and tendentially compatible categories of intervention with the interpretation of the built heritage, from the neighborhood to the building as a “resource” to be renewed and as an opportunity to create economic, social and environmental value. The stock of buildings owned or publicly managed by the Social Housing Public Agency of the Municipality of Rome (ATER) is second only to that of the City of Berlin in terms of size and number of dwellings. It consists of about 670 publicly owned buildings, representing about 25,000 dwellings. The transformation and renovation of this heritage can on one hand improve the overall efficiency of the public housing resource in terms of social, economic and environmental aspects; whilst on the other hand it can have a guiding effect on the heritage, as was the case during the planning phase of the most important social housing districts. The main objective of the experiment carried out is to define, by means of a simulation, potential areas of intervention - managed by the public authority - that can coordinate an action of architectural, functional and environmental regeneration of the public housing stock. Current policies focusing on urban and building regeneration primarily target private property, but there is potential for impactful changes in buildings owned by public entities. This presents an opportunity for rational design choices (Castellanos Garzón & Bustacara Panzza, 2023), https://we.tl/t-pkWdDeiJXc leading to urban, economic, and social regeneration, cost-savings, and energy-efficient buildings. The research can serve as a useful tool for accessing funding for these interventions.

The search for high construction and transformation qualities means not only recognizing the value of an architectural solution, but also understanding its economic value and assessing its real impact on social dynamics. The environmental issue, which requires serious consideration of what happens after the useful life of a building concerns, for example, the fate and impact of demolition waste, but also the invisible ecological footprint of a new building (Marini & Corbellini, 2016). In a not so distant future the integration of these arguments into mainstream urban regeneration processes will largely depend on the strength of planners to incorporate them into their approach to overbuilding the existing.

Typological and technological-constructive innovations, closely linked as in the past, must today address the issues of intervention in the existing building in order to achieve its necessary renovation and transformation^[3]. On the architectural level, the experimentation could be even more interesting and varied, opening it up to many design approaches that can be used in relation to the pre-existences. From this point of view the realizations of the 1st P.E.E.P., due to their morpho-typological conformation, would lend themselves well to targeted functional transformations and densifications, with possible changes of use or the insertion of other functions. The comparison with the often-abandoned spaces of the ground floors and roofs would be particularly interesting. Construction innovation could instead focus on sustainable technologies that can reduce the energy and environmental impact of existing buildings and neighborhoods. In this key, the fundamental objective of the technological and construction experiments of the 1st P.E.E.P. could also be reviewed. The attempts to reduce construction time and costs could concern “green” technologies, trying out solutions to be widely applied later.

Figure 5.Quartaccio, the market’s square.

Credits: Carlo Vannini, 2023.

What has been said so far has a close, multidirectional (reciprocal) relationship with the necessary productive transformation of the construction sector, which must be increasingly oriented towards maintenance, recovery and regeneration i.e. towards qualitative aspects, deviating from the previous quantitative logic based on new construction and urban expansion (Ciorra & Marini, 2011). It would be possible to imagine new specializations and new roles for designers, characterized by relationships with many other professionals and, above all, with the inhabitants. In fact, an appropriate approach to intervening in what already exists would see the professionals themselves in the background, subordinated to the social protagonist, real or potential, completely reversing the logic of design hypotheses to which people should adapt. The integration of design processes shows a virtuous cross-fertilization between art and science in the field of industrial production: this seems to be embryonic for the transformation of the built environment, still limited to the analysis of phenomena and rather paralyzed in design processes, with slow dynamics and conflictual dialectics between the actors, claiming primacy between the creative and executive spheres. Strictly constructive issues come into play in this comparison, as well as the social implications of some choices for their cultural and economic significance, and for their impact on users. Faced with these issues, the figure of the architect as Total Designer^[4] and guarantor of the project, in its Vitruvian connotations, can acquire a new controlling role in the integration of the various disciplines, in addition to the pure design activity, for the entire duration of the building process. In fact, these tools require an open and humanistic approach to counter a fideistic submission to technology, recovering the etymological role of the critical discourse on the evolution of techniques (Paris, 2021), placing the human being once again at the center of a system of concentric circles. To this end, a dialogue should be opened with the humanistic sphere in order to reinvent the future and not to be subjected to it. The recognition of the importance of contexts would be a fundamental aspect of any redevelopment hypothesis, which should therefore always start from the same starting point: the awareness of the fundamental role of the inhabitants in all phases of the management and transformation of their living environment.