Habitat problems

Social interest housing (VIS, for its Spanish acronym)) is considered to be that managed (designed, built, financed) by the State, which responds quantitatively to the demand for housing, and qualitatively, to its quality. Under this conception, there must be a State present that responds to the needs of society and generates equal opportunities for all (^{San Juan, 2017}). If the State is considered a social whole that transcends the actions of a government, it is pertinent to state that the VIS will allude to "everything that affects a society and concerns it"; that is, "A type of housing shortage that society is interested in and must solve". From a solidarity perspective, society thus places on the State the responsibility to solve it (^{Sepúlveda Mellado & Carrasco Pérez, 1991}).

However, the need for housing and habitat of the popular sectors has transcended this concept in recent years, aiming at its resolution in an articulated manner among all the actors involved (^{San Juan et al., 2016}). Habitat issues, then, must be addressed from their complexity, in a systemic manner, developing proposals that tend to be thought of as comprehensive, intersectoral and interdisciplinary, aiming at an integral territorial development (^{Kizka, 2016}). According to Barreto, it is "imperative to avoid an inadequate housing policy for the habitat problem of the most vulnerable households, which only leads to improve some aspects of housing, without contributing to improve the other dimensions related to the habitat problem" (Barreto, 2008). For their part, other studies reinforce this thought, asserting that the inhabitants should be incorporated into the definition of public policies, since they have the skills for it; in this way, governments could manage more efficient and, above all, more democratic housing policies (^{Castillo Couve, 2014}).

In this context, the most vulnerable families who do not have access to state social housing or private enterprises resort to the production of their habitat with great efforts, in a progressive, self-managed way, with scarce economic and financial resources, without social support or technical advice from the State, obtaining precarious or inefficient solutions. There is a need to produce solutions or actions in this process through accompaniment, focusing on social participation at both urban and building scale and, ultimately, in the SPH (^{Romero & Mesías, 2004}; ^{San Juan, 2017}). It is necessary to overcome the welfarist participation of the State, which is not enough to respond to the growing demand for housing, nor does it value the capacities of the communities during the habitat production process, although it is not possible to do without its technical, economic and manage-rial capacity to develop more efficient actions that respond to the possibilities of the families (San Juan et al., 2016). According to ^{Pelli (2007)}, overcoming State welfarism would imply working within the framework of pre-existing capacities and patterns in the different social groups (cultural, political, among others), in order to share knowledge to face future community or individual problems.

Housing as a technical system

The housing problem should be thought beyond the technical dimension that evaluates the production of the work, costs, quantities and types of materials, construction systems and execution times. Instead, it should be thought in an integral and systemic way, incorporating social, cultural and environmental dimensions, and tending to the improvement of its quality (^{Rincón González, 2006}) and its habitability (^{Piña Hernández, 2018}). According to Miranda Gassull, the approach of inhabiting as a technical solution is a technocratic approach that addresses the housing problem quantitatively, where the popular habitat is an ahistorical housing design typology and the role of the architect is a tech-nical profile (Miranda Gassull, 2017). From the approach of the philosophy of technique, Rincón González proposes three orientations or approaches to the housing problem: the instrumental, the cognitive and the systemic (Rincón González, 2006).

The instrumental approach is linked to the technique and technologies (considered knowl-edge) involved in the production of artifacts or products in search of technological innovation and diffusion. It corresponds to a conception proper to the worldview of Modernity, under a logic called technological determinism, and defined by Thomas ^{Hughes (1996}, cited by ^{Rincón González, 2006}, p. 72) as "the belief that technical forces determine social and cultural changes".

In the cognitive approach, empirical techniques make up practical knowledge and the general technique involves a "set of skills and knowledge" that serve to solve practical problems (^{Quintanilla M. 2002}, cited by ^{Rincón González, 2006}, p. 72). This approach facilitates the identification of social and cultural factors that determine or influence technological development. The opposite approach, technological determinism, called social constructivism, is a concept developed by ^{Pinch and Bijker (1999}, cited by Rincón González, 2006, p. 73). In this framework it is stated that "social and cultural forces determine technological change", as an emergent of postmodernity, valuing human, social and environmental aspects (^{Hughes, 1996}, cited by Rincón González, 2006, p. 73).

The systemic approach articulates the two approaches already mentioned, considering the properties of technique and technology (^{Rincón González, 2006}). It includes a technical system composed of physical entities, artifacts, products and social actors that act to modify or transform something.

Understanding housing as a technical system implies the need to consider both the raw material used (technical system) and the material components, whether parts or artifacts of the system, and the agents or social actors involved -individuals or organizations-, characterized by their knowledge and skills. The components of such a system will produce managerial and trans-formational relationships.

Technology for social inclusion

As we have already mentioned, housing is the center of the strategic action of a family and a community to transform land tenure into a fact of protection and family planning, of human and social scale. The object is the possibility of "living better", of leading a healthy life. And if this objective is part of our daily life, why do we have people excluded from this situation?

In this context, technology for social inclusion (TIS, for its Spanish acronym) can be considered a possible strategy for the improvement of the popular habitat, since it aims at the systemic resolution of problems, and not at their specific solution. The development of TIS's, knowledge-intensive for popular habitat, framed in the scientific-technical challenges of research and development (R&D) institutions, would allow communities to take advantage of scientific-technological knowledge, according to ^{Thomas and Becerra (2014)}. In turn, it would aim at social participation in the design, management and implementation of these.

This systemic vision allows speaking of "heterogeneous Social Technological Systems (of actors and artifacts, of communities and technological systems) oriented to the generation of dynamics of social and economic inclusion, democratization and sustainable development for society as a whole" (^{Thomas & Becerra, 2014}, p. 125). They involve the integrative design of products, productive processes and organizational technologies, use goods, inputs and final products, normative and regulatory systems, public services and infrastructure (^{Juárez & Avellaneda, 2011}).

Understanding that housing is a system, that it incorporates different technical subsystems, and that, from an ecological point of view, it works as an "open" system, with inputs and outputs of matter, energy and information, we can under-stand that in order to achieve a correct habit-ability of living spaces -implying a good comfort and a good quality of life for its inhabitants-, efficient buildings or technical objects are required in terms of their operability.

If we translate these socio-technical systems into indispensable requirements for a better life, within the framework of the Sustainable Development Goals (SDGs) (UN, 2015), popular housing must have:

Social production of habitat

Since the 1970s, in the context of the growth of urban settlements due to rural-urban migration, members of different organizations of the Habitat International Coalition-Latin America (HIC-LA) have been jointly developing the concept of SPH, as an extension of the concept of progressivity in defense of popular habitat (^{Di Virgilio & Rodríguez, 2013}; HIC-AL, 2016; ^{Ortiz Flores, 2012}). The purpose of the SPH, framed in the right to inhabit, implies that these social sectors can have a habitat that responds to their demands by means of processes in which they participate and decide, understanding that "habitat is a producing-product in a dialectical process" (^{Romero G., 2002}, cited by ^{Miranda Gassull, 2017}, p. 233).

Enet defines the social production of habitat as "All those processes that generate habitable spaces, urban components and housing, which are carried out under the control of self-producers and other social agents that operate on a non-profit basis" (Enet et al., 2008). It starts from the conceptualization of housing and habitat as a process, and not as a finished product; as a social and cultural product, and not as merchandise; as an act of inhabiting, and not as a mere object of exchange (^{Ortiz Flores, 2012}).

Under this conceptual framework, a methodological development is proposed to arrive at the conception of a systemic model, in order to approach the design of a housing solution.

Context situation

The proposal is located in the urban periphery of La Plata District, capital of the province of Buenos Aires, Argentina. It is a locality with 713,947 inhabitants. It has 260 poor neighbor-hoods, with more than 50,000 families. Most of the housing conditions are irregular, precarious and with little or no access to infrastructure services, pavement and lighting.

The district is located on a high plain, on the edge of the La Plata River, as shown in Figure 2, crossed by streams with a low runoff gradient, according to the following coordinates: 34° 56' 00' South Latitude; 57° 57' 00' West Longitude and 23 masl. The climate incorporates two marked seasons, winter and summer, with prevalence of the former, as illustrated in Figure 2, so it corresponds to bioenvironmental zone IIIb, warm temperate (with thermal amplitudes < 14 °C). The mean annual temperature is 15.8 °C, and precipitation is 1007 mm/year; in winter: annual medT: 9.7 °C; RH: 82 %; GDheating 20: 1668 °C. In summer: annual medT: 21.7 °C; RH: 70 % (IRAM, 2012).

Source: own elaboration (2021).

Figure 2 Location of the La Plata district, bioenvironmental zone. Climatic conditions; design recommendations. 

Detection of critical neighborhoods

The detection of critical neighborhoods was carried out on the basis of previous studies, taking into account the general characteristics of the popular neighborhoods of the GLP. First, the environmental, territorial and social status of each neighborhood was analyzed, conceiving and projecting its housing potential with respect to the construction, location or relocation of the proposed housing. Secondly, the morphological state of the neighborhoods was analyzed, in relation to their extension, consolidation and densification in terms of their potential for helio-energetic insertion.

From the environmental and territorial aspects, those sectors with water risk and potentially dangerous for their inhabitants were taken into account (^{Romanazzi, 2019}). The selection was made according to the level of danger², which allows identifying the neighborhoods with the highest risk. From the territorial and social aspects, population characteristics, buildings and accessibility to infrastructure and basic services were taken into account. A geographic information system (QGIS 3.18) was used to integrate, manage and analyze qualitative and quantitative data using databases from the National Census Institute of Argentina (INDEC, 2020) and the National Registry of Popular Neighborhoods (ReNaBap, 2020), which contain the latest updated information available in Argentina.

Urban insertion strategies

Once the neighborhood was selected, it was analyzed morphologically, through satellite images and in situ surveys, and possible forms of intervention to incorporate housing were determined. Based on the experiences gathered in the bibliography and on the survey of the case study itself, the following insertion strategies were proposed as possible, respecting the current location of the families in the vicinity of the neighborhood: 1) completion of urban fabric by locating housing complexes in empty urban lots; 2) helioenergetic orientation, in the solar north direction of the main facade where solar thermal production systems are located; 3) urban acupuncture, from specific operations, under an organic and systemic concept, understanding the growth of the city as an evolutionary process (^{Lerner, 2005}; ^{Ramírez & Kapstein, 2016}).

The study of the forms of urban insertion showed the need for the design of housing units that had the flexibility to be integrated into urban voids, vacant areas or existing lots, forming groups or incorporating isolated dwellings. Within this framework, the participatory design of the proto-type responding to the above was proposed.

Strategies for housing unit design

Together with the organizations and work cooperatives, the inhabitants of the neighborhoods and the different actors in the governmental and scientific-technical fields, work began on the design of a flexible housing unit from different aspects. The following flexibility alternatives were proposed for consideration: 1) typological; 2) functional; 3) constructive; 4) productive; 5) managerial, starting from a basic (and structural) spatial configuration that would provide the greatest opportunities for design, use, appropriation and construction.

In this way, an initial design was made, specifically in conjunction with a local construction cooperative: the Universidad Nacional de La Plata [National University of La Plata (UNLP for its Spanish acronym)], a wood production technology center of the UNLP and the inhabitants of the neighborhoods. Prior to the validation of the construction process aspects, an energy-environmental assessment was carried out to verify its performance in the climatic conditions to which it would be subjected.

Criteria for environmental sustainability

The housing unit developed was evaluated by means of thermal, energy and environmental simulations, as a method of validating its performance. After its construction, its response was verified by means of an in situ audit. Based on a basic prototype, bioclimatic strategies were incorporated with respect to energy conservation in the envelope, the sun, light and wind. The prototype was modeled and simulated in terms of envelope characteristics, sunlighting, natural lighting, winds and ventilation, using related calculation programs (Google Sketchup, Velux Daylight Visualizer and Autodesk Flow Design, respectively).

Additional alternative technological components

Within the framework of the housing solution, the aim was to integrate architectural components that appeal to simple technologies, that can be self-built or that allow the generation of productive enterprises to improve the habitat and, thus, generate job opportunities.

Detection of critical neighborhoods

To define the intervention sector, all the poor neighborhoods were evaluated based on the interaction of the variables mentioned above. Of the total of 260 neighborhoods, three of them were found to have the highest criticality index: neighborhoods 19 and 90, La Esperanza and La Cantera, in the La Plata district. These cover an area of 64.18 ha, and are inhabited by 1,242 families (ReNaBap, 2020). Figure 3 shows the location of these neighborhoods in the city and in the urban sector, and a detail of the spatialization and their hazard index.

Source: own elaboration (2021).

Figure 3 Intervention area with hazard levels, along with the location of neighborhoods and sectors for urban insertion 

Urban insertion strategies

The sector was selected over the rest of the neighborhoods, given the following conditions: 1) exponential socioeconomic vulnerability with respect to the rest of the neighborhoods, due to the economic characteristics of its population; 2) water risk (floodable area up to 2 m high), with the need to relocate houses; 3) risk of houses located on the edges of the quarry (open pit quarry), with the need to be relocated; and 4) environmental pollution and lack of sanitation, due to the exis-tence of garbage dumps in the area.

As can be seen in Figure 3, the neighborhood had a high criticality index, which also allowed detecting sectors in which to consider the various possible insertion alternatives.

Based on the urban insertion strategies defined, three sectors of the neighborhood were identified where new housing could be located. They are shown in Figure 4.

Source: own elaboration, based on Google Earth (2021).

Figure 4 Development of urban intervention strategies. 

For sector 1, the proposal of completing the fabric was applied, which is based on the incorporation of a set of twelve dwellings organized in a system, in order to generate a community environment. The interface between the neighborhood and the dig was resolved by considering it an environmental liability, through the incorporation of a linear park, where urban facilities, sports sectors, fairs, vegetable gardens, meeting and social exchange spaces are located, as shown in Figure 4.

For sector 2, the proposal was located on one of the edges of the consolidated grid, adjacent to the vacant space, on a " tagliatelle" type block (elongated), and relocating precarious housing, based on the urban strategy of helioenergetic orientation, with its main facades fully oriented to the solar north. Public facilities, work sectors, organic vegetable gardens and community meeting spaces were incorporated, as illustrated in Figure 4.

For sector 3, the proposal responded to the strategy of urban acupuncture, where individual or paired housing units were incorporated into the existing fabric on vacant land, in order to respond to families who required decent housing. In addition, a small housing complex with its social facilities was incorporated into the proposal, on vacant public land, as shown in Figure 4.

The possible ways of intervening in the neighborhood required a flexible housing unit proposal, which responded to the possibilities of individual or group housing, within the frame-work of a sustainable design.

Strategies for housing unit design

According to the proposed urban insertions, the project logics were established with the objective of: addressing a housing emergency situation; incorporating knowledge (popular, academic and managerial); improving the quality of life in the popular habitat; promoting the training and education of producers of the popular habitat; encouraging self-organization and co-management of the habitat; generating actions that promote production and labor; developing spaces for neighborhood integration and exchange, and encouraging the promotion of rights, as well as the construction of equality, equity and social justice.

Under these criteria, the solution was integrally solved in light technology (wood), both in its resistant spatial structure and in its envelope (floor, walls and roof), as well as in its enclosures (doors and windows) Figure 5. Shows some regional examples of the benefits of this type of construction (^{Filio Reynoso et al., 2017}).

Source: own elaboration (2021).

Figure 5 Exterior and interior perspective of the housing solution. 

As mentioned in the methodology, the strategy adopted was to achieve maximum typological, functional, constructive, productive and managerial flexibility.

In terms of typological flexibility, a basic module was proposed, in linear organization, with minimum dimensions, which involves a living-dining room, kitchen and bathroom, that can be expanded into one or two bedrooms, with the same construction system, as shown in Figure 6. It may correspond to a housing space with individual or paired location on a plot of land. The covered space, in its perimeter layout, has semi-covered galleries that protect it from the outside environmental conditions.

Source: own elaboration (2021).

Figure 6 Detail of the base module. Functional Unit and growth. 

Regarding functional flexibility, the housing solution formed a functional unit (FU) which involved a covered space, access area and natural terrain. The main covered space initially had a surface area of 22.5 m2, to which the storage space (refrigerator, closet, shelves, salamander) was added, as shown in Figure 6.

Concerning construction flexibility, the proto-type was of dry and serial construction; its systematized components were materialized in the workshop (wooden rings and 1.22 m X 2.44 m modular panels), which allowed their production in considerable quantity and in advance, in order to respond to emergencies. These conditions made it possible to quickly assemble the prototype in the field, reducing waste production, saving materials, providing flexibility in terms of enclosures and the use of recycled materials, and improving the working conditions of the builders, as shown in Figure 7.

Source: own elaboration (2021).

Figure 7 Resistant spatial structure; quartering; progressive assembly, and participative management of the local work cooperative, the technicians of the IIPAC-FAU-CONICET-UNLP and the Centro de Tecnología en Madera (CTM) of the UNLP. 

With regards to production flexibility, the shaping of parts, components and additional systems was carried out entirely in the workshop [Centro de Tecnología en Madera, Wood Technology Center (CTM, for its Spanish acronym), belonging to the UNLP], and the assembly of the habitable unit, in the territory. It was verified that the system was suitable to be produced by social organizations acting in the area (tools: training course, procedures manual, audiovisuals), as shown in Figure 7.

And with respect to management, undertak-ings were considered within the framework of participatory project management (PPM), through a systemic multi-stakeholder management model. For this purpose, the work was done with a labor cooperative from La Plata district , which participates in the Social Council of the UNLP with support from professionals and technicians from the Faculty of Architecture and Urbanism of the UNLP, as also shown in Figure 7 (^{San Juan, 2017}).

Once the housing unit was designed, environ-mental simulation analyses of different variables were developed to verify its correct operation.

Criteria for environmental sustainability

Since this socioeconomic sector has restricted access to basic energy services (electricity and gas), and as most of them live in energy poverty (^{García Ochoa, 2014}), the energy demand for air conditioning (winter and summer) was optimized in the housing proposal by including thermal insulation throughout the building envelope. Comparing the same prototype with three technologies, according to Level "B" of the Argentine National Standard (IRAM, 2012), by reducing air renewal (AR) and allowing cross ventilation, comfort conditions are improved and energy consumption is reduced. If we consider that a precarious dwelling (simple wood and sheet metal envelope without insulation) consumes a relative value of 100%, a traditionally built dwelling (hollow ceramic bricks 0.18 m thick and sheet metal roof with minimum insulation) would demand 45%, and the proposed housing solution, 23% of the initial housing demand, thus improving its indoor comfort, as shown in Figure 8.

Source: own elaboration (2021).

Figure 8 Energy and light simulation and sunshine analysis. 

Likewise, the solar incidence and the generation of shadows at the level of the housing unit and the proposed helioenergetic complex were verified, so that there is no shading between units or on the building unit itself, verifying its access in the winter period (June 21 at 10 am) and its control in the summer period (December 21 at 10 am), as well as the sizing of the galleries, as shown in Figure 8.

The design, type, size and location of openings, as well as the reflective coefficient of the interior surfaces (white surfaces), achieved a correct natural lighting on a plane at + 0.80 m from the floor level, thus reaching an average illuminance level of 408 lux in the main spaces, which is sufficient, and this, in turn, means not having to turn the lights on during the daytime period, as shown in Figure 8.

The natural ventilation system for the summer period was taken into account by incorporating cross ventilation through opposite windows and minimizing the surfaces with unfavorable and selective night orientation. For this purpose, a south-facing window (0.50 m X 0.50 m) and ventilation ducts were incorporated in the roof. Likewise, the incidence (direction and speed) of outdoor winds in each unit was verified, as shown in Figure 9.

Source: own elaboration (2021).

Figure 9 Effect of cross ventilation in summer through opposite openings (left) and incidence of wind in winter (right). 

The housing unit has good thermal, light, wind, ventilation and energy response, with an energy demand four times lower than in a typical precarious construction, with average lighting levels of 400 lux in contexts where, generally, they do not exceed 100 lux, with good ventila-tion and wind protection.

Additional components

The housing solution incorporated a series of additional systems or components, previously developed and published by the R&D team, which were alternatives to those available on the market, and which are low-cost, of simple materials and construction, and environmentally friendly, as well as feasible for self-construction or to add value to social cooperatives. All of these are shown in Figure 10: solar water and air collector, modular sanitary partition, alter-native thermal insulation ([] = 0.06 W/m2 °C), safe electrical system and effluent treatment. These alternative systems were developed from the exchange of knowledge between the target communities and academic-scientific groups of the work team. This R&D technology, as well as the living space, were oriented to the creation of productive micro-enterprises, with the consequent generation of salaried work.

Source: own elaboration (2021).

Figure 10 Additional alternative components to those on the market developed in completed research and development projects.