Resumen de 'Barrios y sostenibilidad. La aplicación de criterios sociales, medioambientales y económicos en el diseño y evaluación de procesos de regeneración urbana sostenible en ciudades europeas.'

María Ángeles Orduña-Gañán

• 1. Neighbourhoods and sustainability. Approach and dimension of the problem The long and pronounced economic crisis, currently affecting numerous countries, has relegated to the background other important and deep rooted crises for the last few decades. Especially, the environmental crisis: a global scale problem recognised by the scientific community and that so far, remains unresolved. While it is true that in recent months, precisely occurring in the international political scene, a glimpse of reconsideration brings optimism and shows a willingness to change, hopefully a definitive change. In the environmental crisis, cities have a prominent role, as discussed below, hence the need to reconsider urban models.

  This research, focuses, amongst all possible urban politics to improve the situation, on the sustainable regeneration of obsolete residential neighbourhoods. For various reasons. Of environmental measures: stopping urbanised footprint increase in favor of the recovery of the existing urban fabric, or the improvement of energy consumption in antiquated buildings, impacting significantly the reduction of energy consumption and, therefore, the emission of greenhouse gases (GHGs); Of social character: improving living conditions, comfort, the quality of life of vulnerable or degraded neighbourhoods, will lead to a more equal and fair consideration of many disadvantaged citizens; Of economic nature: channeling, public and private investment in the recovery of fabrics, that despite their poor current conditions, have great potential to revive an ailing economy.

  1.1 The environmental crisis and the need to reduce emissions of greenhouse gases. The implications with the social and economic crisis According to population data from the United Nations, more than half of the world population, 54%, live in cities and the tendencies point in this direction. It is anticipated that by 2050 this figure will become 66% . In the specific case of the European urban dweller, the proportion is approximately at 80% and in Spain, it is estimated at 70% .

  At the same time, it has been found that cities are responsible for up to 70% of the production of GHGs contributing to climate change, thus becoming the battlefield against global warming . Therefore, it can be said that the sustainability of the planet is conditioned largely by sustainability in cities and similarly, the needs of current and future citizens can only be guaranteed through sustainability.

  Climate change has severe effects on the planet and its inhabitants. Global warming contributes to sea level rise and increased hydrologic natural disasters , among others. These factors concern the world's population, sometimes dramatically. And while it is true that the consequences of climate change affect everyone on the planet, the consequences are very different if they occur in rich and poor areas. Therefore, acting in favour of urban sustainability is also a measure of solidarity with the inhabitants of the planet, especially the poor. It can be understood, therefore, that the ecological crisis is a social crisis. Natural ecosystems have depend on human society for a long time, it is no longer possible to separate: nature and society. The scientific community has made it evident that the environment is in crisis, due to uncontrolled actions of human beings on the environment. But this human action, harmful to the planet, is produced asymmetrically, this, made evident by some social philosophers. An estimated quarter of the world population consumes three quarters of the planet's resources , this can relate the environmental crisis and social inequality on a global scale.

  But the environmental crisis as well as being linked to the social crisis, is linked with the current economic crisis, being that global economy has consistently wasted natural resources and sources of increasingly scarce non-renewable energy. The economic crisis is linked to the shortage of fossil fuels that are largely responsible for the environmental crisis. The era of cheap energy is running out and this fact has an enormous influence, especially, in the monetary and financial sectors of the economic system. In fact, the economic system currently in force on the planet, not only is reaching the limits of the biosphere, but is also increasingly favouring situations of social inequality. The three crises are, therefore, also interrelated.

  Fortunately, in recent months, from the international political arena, a shift is seemingly developing, a hint of willingness to shift towards eliminating this problem. In June this year, 2015, the G7 (The Group of 7, the seven most industrialised countries in the world), have confirmed their intention to undertake a shift to a free model of GHG emissions and their commitment to prevent increasing the temperature on the planet. For this, the IPCC proposes reducing emissions by between 40% and 70% worldwide between 2010 and 2050, to reach a zero level in 2100 . The ultimate accolade for the end of climate change could take place later this year at the UN summit in Paris, where it is expected that governments will approve a protocol to replace the expired - and noncompliant Kyoto.

  1.2 The paradigm of sustainability and it’s attributes The first definition of "sustainable development" is expressed in the famous "Brundtland Report" of 1987, as one "that meets the needs of the present generation without compromising the ability of future generations to meet their own needs." Throughout the nearly three decades since the quoted report proposed the concept of sustainable development (a concept sufficiently open and even ambiguous to provoke a general consensus) much has been written, aiming to defining its meaning and unravel the keys to its success.

  One of the most complete definitions, so far, to understand this idea is to understand sustainability as a product of three axes: the environmental axis, the social, and the economic, all interrelated inextricably. Already in 1994, the International Council for Local Environmental Initiatives (ICLEI), defined sustainable development as "one that provides basic environmental, social and economic services to all members of a community without threatening the viability of the natural, built and social systems upon which the supply of these services relies." This transversal approach and need for action in the three axes: environmental, social, and economic set the idea of sustainability until that moment and marked a shift in the approach to this problem.

  Likewise, the "Grupo de Expertos sobre Medio Ambiente" (Eng., the Panel on Environment) of the European Union in its report "Ciudades sostenibles" (Eng. Sustainable Cities) identifies the following basic principles of sustainability: • Environmental limits. Human activity must adhere to the limits imposed by the natural environment, no apparent benefit can therefore compensate for the damage exerted on the planet.

  • Management of the demand. Procedures must be enabled to reduce or redirect certain demands within environmental limits, instead of meeting them without question.

  • Environmental effectiveness, i.e., obtain the maximum profit per unit of resources used and waste produced.

  • Social effectiveness, equivalent to the former for the social field.

  • Equity. This principle seeks the equitable distribution of wealth, of natural resources and energy among all the peoples of the world. Social solidarity is, therefore, an important principle of sustainability.

  1.3 The paradigm of sustainability and its quantification: the use of indicators and criteria With the paradigm shift, the emergence of the concept of sustainability and the need for its measurement, starts to give higher relevance to the use of indicators. Indicators are probably, since the Rio Summit in 1992 , the most widely used system for monitoring and evaluation of sustainability. However, although there are numerous sets of indicators to measure sustainability, there is no scientific or institutional agreement on what is the best way to proceed; nor is there a consensus on the definition of the indicator concept.

  Indicators An early definition for indicator was set forth in 1966 by Bauer, defining indicators as "statistics, statistical series, and all other form of evidence that enable us to assess where we stand and are going with respect to our values and goals, and to evaluate specific programs and determine their impact." The choice of indicators, their definition and method of measurement depend on the decision of the professional who develops them and therefore are also influenced by the purpose and intent of the work for which they are synthesized. For this reason, several authors find that there is no single model of indicators or a universal set of indicators.

  Standards Before the proliferation of indicators such as measurement and evaluation, there existed in the nineteenth century standards that set necessary anchored minimum values, as a difference to indicators, allowing zoning laws to ensure urban quality. Standards are "quantitative parameters or optimum dimensions, variable in time and space, on the functions or requirements to be met by man when constructing cities and, in general, making changes or preserving natural spaces". The standards and indicators are of great value to quantitative evaluation, since with them reference values can be set to meet the task. But for proposals, evaluation of urban transformation, quantitative assessment is not the only important tool.

  Criteria, qualitative data list, checklist In urban regeneration projects there are factors that can not be quantified, nor is it possible to obtain a direct measurement by means of a numerical value reference, but certainly they can be evaluated with other attributes, besides establishing a relationship with other complementary indicators .

  Criteria can be defined as "standard to know the truth." It is "a characteristic or property of the project in which you can rely, to judge or make decisions." The checklist is a tool that helps ensure consistency and thoroughness in carrying out an action. It is a mechanism of verification, confirmation of the truth or accuracy of the actions.

  Next is a summary discussing the project’s research on variables and their meaning for the purpose of quantifying and qualifying the actions of sustainable urban improvement.

  Definition Synonyms Indicator Quantitative variable representing an empirical model of reality Indication, reference, monitoring instrument, value (statistical) Standard Quantitative parameter defined by an authority to ensure the quality of certain actions Standard, type, pattern Reference value Numerical value (an indicator) serving as a reference to help evaluate and compare the level of success achieved Reference, measurement Criterion Requirement, standard to be met to achieve a goal. Characteristic or property to lean on, to discern and make decisions Brand, property, characteristic, condition, attribute Table 1: Definition and synonyms of variables for evaluating sustainability Author prepared 1.4 The role of the Neighbourhood as the basic urban unit In the present research, the neighbourhood scale is proposed as the appropriate scale for action upon urban sustainability. In the history of the city and that of planning, the neighbourhood has been considered as the basic unit of formation and functioning for cities. For Lefebvre, the neighbourhood is the natural ambit of social life, and, the social unity at human scale. Contact point between the geometric space and the social; the neighbourhood is ambit of perception, identity, belonging and ownership, place for the multiplicity of social networks and citizen participation.

  This is how it was understood by planners of the early twentieth century. For example, when Clarence Perry gave naturalisation to the concept of the Neighbourhood Unit in the Regional Plan of New York and its surroundings (1929): relatively autonomous residential areas, roam-able on foot, with the school as a basic endowment, with public socialisation spaces, covered primary commerce, employment opportunities and/or public transport to go to jobs. His influence on the planning has been clear: adopted by the CIAM , used by Abercrombie or in numerous recent proposals.

  Although there is no consensus or a single definition for the concept of -neighbourhood-, in this research -it-, is understood as a minimum cell that forms a city, where the social fabric and networks of support among neighbours are built, where the idea of belonging or identification of citizens develops, creating a sense of city. Precisely the anthropological aspect of the neighbourhood as a space for citizen identification, to form "part of something", to recognise when in it or out of it, is a value that although difficult to define, is displayed as the most effective way to promote sustainable urban regeneration.

  The neighbourhoods of European cities, although some in state of degrade, count on great initial resources; the urban physical layout and the social layout, which with adequate focus and according to principles of sustainability, can be reactivated, redirecting the future of cities towards improving the quality of life for residents and their relationship with the natural environment.

  1.5 The obsolescence of the suburbs of the twentieth century in European cities According to many authors, European cities, especially their physical and socioeconomic structures, have been significantly affected by the restructuring and changes in the economy, formerly dependent on heavy industry and its production modality . These effects are more evident in neighbourhoods built in periods of massive influx of people looking for jobs and opportunities, where even today, many residents live within a vulnerable social profile; where environmental quality is lower; where less profitable economic activities coalesce; and have been expelled from areas of greater centrality.

  These same cities, on the other hand, have well equipped attractive areas, where museums, well kept housing developments, institutional buildings, fountains and high street shops, increase the quality of the urban imprint. They are, therefore, unequal cities that allow the coexistence of elite areas juxtaposed to other areas clearly not reaching a desirable minimum . The current economic crisis only serves to deepen the difference between the areas, causing a growing social inequality and exclusion. According to the European network of Neighbourhoods in Crisis "many European cities have `neighbourhoods in crisis´... this increasing the gap between profitable areas of the city and the poorer areas that do not benefit from the situation of the first." The obsolescence and the deterioration of these neighbourhoods does not respond, usually, to a single problem, but to certain starting point characteristics that make them accumulate various kinds of pathologies that make them unsustainable: streets without quality, equipment deficits, green area deficits, or bad conditions of the same, monotonous urban typologies, aged buildings with very small housing, with poor insulation and humidity problems. With a social profile marked by a large group of workers in an unstable situation, with family incomes and purchasing power below city average levels. To this we must add that in some cases, these areas are home to the immigrant community and even enclaves of drug dependency or prostitution.

  They require improved integrated policies that influence many fronts and allow recovery for cities in certain areas, which on the other hand, are very valuable. Valuable because they count, for the most part, with a social fabric that makes them a vital and important part of the city, with close knit social relationships and a high degree of belonging to the neighbourhood. Valuable because they make a City, contrary to what happens with newer growths of dispersed nature. Valuable, in short, because they harbour a lot of "grey energy" , which makes them very attractive from an environmental point of view (although their buildings may specify unavoidable energy saving and efficiency improvements).

  1.6 Regeneration of neighbourhoods versus new residential developments as a guideline for urban sustainability The Committee of the Regions, in its dictum "The role of urban regeneration in the future of urban development in Europe" makes clear that the new model of a sustainable city should rely on an innovative integrated approach to urban revitalisation and that in consonance with the Leipzig Declaration, takes into account environmental, economic and social aspects. Then, it would be deserving to propose urban regeneration, placing the city facing environmental problems as a strategic policy, to promote a more equitable, cohesive and attractive city, and to stimulate the economy.

  Many authors, including Naredo, report that the problem of urban sustainability at European level has worsened due to the conurbations of low density built in the last, very wasteful years of resources and energy use, besides being major generators of wastes. It is estimated that these low density urban fabrics generate land consumption and a longitude of roads 10 times greater, as that of urban tissues of medium-high densities . For the user, it is also estimated that to live in one of these low density conurbations, can be 6.5 times more expensive than in a compact urban area .

  Sustainable urban regeneration, as defined by the "Group of experts on urban environment of the European Union" is the "inversion process of economic, physical and social decline of the existing city, where decline has reached a point that market forces cannot overcome alone." This perspective, where the cultural, environmental, social and economic planning and architectural aspects, are worked at the same level of importance, is a new model to understand and address the actions of the existing city, the object in need for intervention.

  The goal of a more sustainable urban development is to support a good quality of urban life with the reduced harmful impact of cities on global sustainability. The recovery of degraded urban fabrics, in which the operation of its urban cycles is improved by ecological standards, as well as by seeking the permanence of the resident population, strengthening in this way its capacity to act in their environment, promotes a gender-mix-tissue neighbourhood (not only residential, but also of leisure, work and production), to improve the quality of life of residents, wagering on the quality public space, etc.; develops a comprehensive transformation that transcends the environmental sustainability, to result in the empowerment of the social factors, businesses and citizens who share the paradigm shift and also transfer it to their behavior and personal lifestyle, causing a metamorphosis towards guidelines, policies and cultures of sustainability.

  2. Investigation. Objectives, methodology and hypothesis 2.1 Objectives The objective of this research is to develop a matrix of indicators and sustainability criteria, organised into the three axes identified by ICLEI: social, environmental and economic, applicable both to assessing urban regeneration projects already completed, as well as the intervention in new areas. Although the intended research is on sustainable regeneration of obsolete urban areas of medium-high density in European cities; it is developed, specially, for the neighbourhoods of the first adjacent periphery suburbs of Spanish cities built during decades of massive influx of people from the countryside to the city.

  The choice of case studies (see Anexo section 3.1 Selection of cases), the discussions held in the course of development of international forums, and the opportunity to carry out part of the research under the International PhD framework, at Humboldt University Berlin; have enabled synthesising generalisable conclusions that can be applied to the European context. Now, this research arises from an identified need in a Spanish area and is carried out, based and has an address in a Spanish university and therefore seeks to be applied, especially in this area.

  Although sustainability indicator listings abound in specialized literature at local and global scale, it is not easy to find a system of criteria and indicators applicable to both the development and evaluation of processes for sustainable neighbourhood regeneration. Hence the interest of this investigation to elaborate on the subject. Many of the existing batteries of indicators are defined by formulas, sometimes, with very stringent requirements on provision of information and too concerned with the quantification of sustainability. In the present investigation it is deemed that non-quantifiable elements also help to understand the reality and promote the success of sustainable urban transformation processes, seeking complementarity by strengthening one another and with consideration of the interrelations between the three axes of sustainability.

  In the deteriorated neighbourhoods for which this work is intended, not only are the problems grouped in the buildings (related to habitability, comfort and energy efficiency) but also to problems of social character (conflicts between collectives, crime, insecurity, etc.) and the economic (lack of opportunities, lack of attractor elements, unemployment, etc.). In turn, as discussed in previous chapters, sustainability is an issue that not only concerns the environment but is interwoven with social and economic aspects. Hence the search for indicators and criteria from the three perspectives above. In turn, the research results show an interaction and interdependence between one and another field whilst simultaneously, not being able to make a unilateral approach from any of the three axes whilst excluding the effects and synergies regarding other fields.

  2.2 Methodology The research is based on three fundamental parts: a documentary part, an analytical-experimental part and a final part distilled from both, which proposes the matrix of criteria and indicators itself (to which reference has been made in the previous point). The three parts are carried out in parallel, so that the end result (the matrix, the work’s objective) evolves thanks to the iteration and feedback between each other. Also, the documentation search, or the analysis of cases has been "directed" at least in part, by the "needs" of reinforcement for defining the set of indicators and criteria.

  The theoretical-conceptual part is laid upon the review of concepts and variables to be taken into account at the time of performing useful contributions in the field of sustainable urban regeneration. With the goal to situate the state of the art and to define a solid theoretical framework that cements the research’s objectives, analysis of texts (manuals, articles, institutional papers, conference papers, books and/or corresponding town planning legislations) currently carried out in Spain and Germany, that directly and indirectly tackle the subject-matter are addressed in this work.

  Figure 1: Matrix methodology elaboration of the criteria and the indicators Graphic synthesis of the methodology followed in the investigation. Prepared by author The analytical-experimental part of the research is based on the approach to reality, to the practical application of the theoretical assumptions analysed in the previous part. This allows to confront a free framework of economic, administrative, legal, social or any other type of development that any urban intervention carries, with proposals of the same complexity, necessarily adjusting, qualifying and modulating. This confrontation results, according to the results obtained at the end of the investigation, in fruitful opportunities to extract conclusions and proposals from the developmental repertoire of criteria and indicators. The methodology put into practice is therefore supported, as in Eckhart Hahn's work and that of the "International Best Practices Contests Dubai" in the practical analysis of various projects, drawing theoretical conclusions of great value, on which it is based, together with the theoretical discussion and analysis, the identification of reference criteria, indicators and values proposed, also applicable in other contexts.

  Areas of discussion of research Discussion with actors within field case studies in Berlin (Prenzlauer Berg and Kreuzberg) and Barcelona (La Mina and Trinitat Nova). Discussion at university level with other researchers and specialists in the field. Congresses, seminars, conferences, etc. where the research work is exposed and discussed.

  Meetings with actors of the process: - associations - technicians - representatives of the administration - neighbours, etc. Colloquium with researchers at Humboldt University in Berlin. "Jornadas de Rehabilitación Ecológica de Valladolid". (Eng. Conferences of Ecological Rehabilitation of Valladolid) Contacts with other researchers both in Germany and in Spain. "Mejoramiento barrial como respuesta a una ciudad para todos". (Eng. Neighbourhood improvement in response to a city for all).

  National University of Colombia "Seminario Internacional de Investigación en Urbanismo". (Eng. International Research Seminar in Urbanism).

  Polytechnic University of Catalonia Antwerp Summer University: "City Development - past, present future".

  University of Antwerp Table 2: Areas of discussion of research Summary of the three main areas of discussion of the research process. Prepared by author For the development of the methodology based on case studies, two Spanish cases have been selected (located in Barcelona) and two German cases (in Berlin), different within each other, but with common problems that often re-occur in other troubled neighbourhoods of European cities. (See Anexo section 3.1 Selection of cases). Among the selected neighbourhoods: there are neighbourhoods of different sizes, year of construction, with regeneration processes underway or completed, with different residential typologies and also different obsolescence situations. This allows us to define a generalizable matrix of indicators and criteria, not strictly linked to too homogenous and specific circumstances.

  In short, the criteria matrix and result of this work (see Anexo section 4.2 Matrix summary), is the product of an iteration within the development process of the research, which combines both theory and analysis of case studies and discussion with different actors who have participated in the process of regeneration (including residents themselves), as well as researchers and specialists in this field.

  2.3 Hypothesis The research parts from the consideration of sustainable urban regeneration in obsolete neighbourhoods in European cities as one of the most effective urban policies in these times of environmental, economic, and social crisis. Proposes the combined use of indicators and criteria, in order to understand the current approaches and to implement future interventions in this complex and multifactorial policy. In this sense, the resulting matrix will help to unravel the scope of such interventions.

  On the other hand, the research suggests that the system of indicators and criteria applied to urban regeneration would bring objectivity and democratization in decision-making processes, both for politicians, technicians and the general public. Apart from making them clearer and more understandable for all stakeholders, such objectivity would result in greater ease to arbitrate participatory processes. Similarly, the matrix of criteria and indicators resulting from the research would provide guidance, a framework for fruitful debate.

  The diversity and number of cases analyzed make it possible to obtain universally valid generalizable results, at least for their use in European cities. Hence, despite the particular circumstances of the starting point, common seminal aspects are taken into consideration, whose validity can be tested, even when considering the need to incorporate particulars to proposals for each area.

  Finally, a number of carefully chosen criteria and indicators, will have multiplier effects, synergic effects. Beyond minimizing environmental impacts, the effects and results will be transversal, affecting social and economic issues.

  3. Case Studies. Berlin and Barcelona 3.1 Selection of cases The analysis of the four case studies is approached from two perspectives; the first, to identify strategies that have proven successful for use in developing criteria and indicators of the matrix; the second, to test the criteria and indicators already identified and induce the necessary iterations in the matrix to achieve an effective tool.

  Berlin is chosen to identify case studies within European scope , as it is one of the pioneer cities with most experience in the field of sustainable urban regeneration and on the other hand, belongs to the German state, which counts with a great track record in this field. Berlin is also one of the key cities to study urban transformation processes that have served not only aspects of ecological form, but that are also heavily charged with the social (especially social cohesion) and economic sectors, due to political-historical circumstances before and after the fall of the wall.

  In the Spanish scope, the city of Barcelona is chosen because it belongs to Catalonia, the only autonomous community with a specific legislation on urban regeneration, the well known "Neighbourhoods Act" of 2004, recently replaced after the entry into force of the "Rehabilitation, regeneration and urban renewal Act" in 2013, that has counted on an administrative structure prepared to carry it out, as well as neighbourhood improvement experiences awarded at national and european levels.

  Although the building typologies and dates of construction of the neighbourhoods of Prenzlauer Berg and Kreuzberg in Berlin do not appear to have much in common with the Spanish expansion neighbourhoods of the second half of the twentieth century, such as La Mina and Trinitat Nova, in essence, they have many similar characteristics. These neighbourhoods have been built with an urgency to meet pressing housing needs and have been occupied since their origin by workers, immigrants and young people with vulnerable social profiles; in situations of poverty, exclusion and crime, where physical deterioration of the buildings, public spaces, lack of urban facilities, accessibility issues, environmental issues, etc., are detected.

  Although originally the four neighbourhoods occupied peripheral sites, they have passed on to enjoy a relatively central position, due to the large urban development of cities, or their historical becoming. To this type of intervention we must add another common and radically important aspect: the strength of social movements, largely responsible for "provoking" urban regeneration projects.

  The four case studies chosen are exemplary cases of transformation of the existing city, from which implementable strategies can be drawn in other contexts. In these areas, action over environmental performance improvement of the built substance, is transcended to find social as well as economic urban transformation sketches.

  3.2 Case Study Analysis of Kreuzberg Kreuzberg is currently part of the Friedrichshain-Kreuzberg district of Berlin. It has an area of 20.2 km2 and 268,831 people live in it. It is one of the higher density districts of the city (13,335 inhabitants/ km2) and is located immediately south of the centre (Mitte). When the city was divided, Kreuzberg was left on the west side of the wall, the sector in which the Americans took control.

  Map 1: Delimitation of the Kreuzberg area of study In magenta the field of study, in blue the path of the wall. Bottom left, the location of the Neighbourhood in the town of Berlin. Prepared by author, from Map 1: 5000 Senatsverwaltung Berlin The fact that the wall surrounded most of the neighbourhood, on three of its sides, caused a rupture of the thoroughfare network connecting it to the centre of Berlin. So, even though geographically Kreuzberg is located in a central position in the city, the neighbourhood was shifted to the periphery, due to the loss of connectivity with both the city centre and the other neighbourhoods. This fact made it possible for a particular alternative culture to originate, different to that of West Berlin, more participative and demanding, and decisively influencing the process of urban regeneration.

  To better understand the scope of regeneration it is suitable to know some facts about the situation of the residents prior to the transformation process: a quarter of the neighbours were young or children (25% versus a 17% average in the city of Berlin at that time), and 50% of the families in the neighbourhood were foreign. It was the poorest district of West Berlin: 14% of the residents lived on social allowance, unemployment affected 60% of its inhabitants and school dropouts averaged about 25% . In addition, there was a large number of empty housing and very high levels of air pollution due to industrial activities incompatible with residential functions and also because of the coal heaters, a regular heating system at the time. The neighbourhood was poor both in services and facilities as well as in green areas.

  Even parting from such a difficult scenario, the urban regeneration of Kreuzberg was a milestone and laid the foundation for the subsequent processes of urban regeneration in the city of Berlin. It was a long process that began in the seventies and ended at the end of the eighties, straddling between the claims of citizen movements, the first implementations of the theories of urban ecological restructuring of Eckhart Hahn and careful urban regeneration, formula, the last coined by the newly founded STERN , that has continued to implement many of the strategies then innovated in the current neighbourhood regeneration projects.

  3.3 Case Study Analysis Prenzlauer Berg Prenzlauer Berg belonged to East Berlin (capital of the former GDR) when the city was cut off by the wall. From 2001 and until today, Prenzlauer Berg belongs to the new district of Pankow, situated at the north municipal terminus of Berlin. It is the second district of the city in size and the most populous of the twelve districts that make up the urban area of Berlin. Consisting of 1384 hectares and with some 370,000 inhabitants. It borders the centre (Mitte) to the southwest, with Wedding at the west and with Friedrichshain to the southeast, Lichtenberg to the east and towards the north, within the same and current district, with Pankow and Weiβensee.

  Although the research study takes on Prenzlauer Berg as a single case study and has been analyzed as a whole, in reality, the urban regeneration project is divided into five areas of parallel action. When Prenzlauer Berg is referred to, it refers to the regeneration of the following areas: Kollwitzplatz carried out between 1993 and 2008, Winsstraβe between 1994 and 2011, Bötzowstraβe between 1995 and 2011, Teutoburger Platz (1994-2013) and Helmholtzplatz (1993- planned 2015, even without conclusion). The three areas of action are homogeneous because of the character of the building as well as the origin and social profile. They are part of the same urban regeneration project and have also been coordinated by the STERN. The division into areas of action is related to the vast size of the area: 256 hectares on which more than 48,000 people live (in more than 32,000 homes).

  Map 2: Delimitation of the study area Prenzlauer Berg 1: Kollwitzplatz, 2: Winsstraβe, 3: Bötzowstraβe, 4: Teutoburger Platz y 5: Helmholtzplatz. Prepared by author, from map 1:5000 of Senatsverwaltung Berlin and data from STERN Included in the starting point data of the neighbourhood’s situation in the early nineties (before regeneration) the following is highlighted: 88% of homes had a coal-burning stove as the only heating system, 43% of households had no bathroom, and 22% had only one toilet on the outside of the housing. There was a high percentage of empty homes and commercial premises, and the state of buildings was bleak. The air quality was poor as were the facilities and green areas.

  The urban regeneration project of Prenzlauer Berg achieved, amongst others, to improve the quality of green spaces and existing street urban spaces by drawing the participation of neighbours and the support of institutions. Both new public and private green spaces are incorporated, energy use in district heating systems and cogeneration improves, old industries spaces are reused and converted into new businesses, compatible with residential use and new facilities, some self-managed, are promoted.

  3.4 Case Study Analysis Trinitat Nova Trinitat Nova is one of thirteen districts belonging to the current district of Nou Barris, located to the northeast on the outskirts of Barcelona. The Neighbourhood of Trinitat Nova is located at the entrance to the city of Barcelona from Montcada, and is bound to the east by Meridiana Avenue, on the west by the Ronda de Dalt and on the north by the Sierra de Collserola, these pathways defining a triangular shaped urban area.

  7483 inhabitants live in the Neighbourhood of Trinitat Nova , within an area of 0.6 km2, resulting in a density of 13,363 inhabitants/km2 . According to the City of Barcelona, a quarter of the neighbourhood’s population is currently composed of immigrants (nearly 25%) and is the poorest area of Barcelona, as stated by the ranking of family income conducted in 2013 and published in January 2015. At present, the process of regeneration of the neighbourhood has not been completed, with more than 130 families remaining to be relocated in new housing blocks, because, as noted further on, some of the buildings built in Trinitat Nova between the fifties and sixties have aluminosis and carbonatosis . The current economic crisis has not helped to improve the expectations of the residents of Trinitat Nova, "at least 60% of the families in the neighbourhood have all family members on strike, and the rest, of course, have an unemployed family member" .

  The construction of the Neighbourhood of Trinitat Nova begins in 1953 in a sudden and improvised form, promoted by three agencies: the Obra Sindical del Hogar (OSH) (Eng., Syndicated Home Labour), the Instituto Nacional de la Vivienda (INV) (Eng., National Housing Institute) and the Patronato Municipal de la Vivienda (PMV) (Eng., Municipal Housing Board). The construction of the first 597 homes began in the middle of vineyards, with no infrastructure or urban planning. Ten years later, 1963, more than 3,000 homes had been built, accommodated within open block residential buildings in which more than fifteen thousand people lived. During the eighties and nineties, the Neighbourhood Association of Trinitat Nova continued to fight for improvements in the neighbourhood, especially after 1991, when Aluminosis problems were detected in the PMV blocks . The Neighbourhood Association lead a citizen movement, demanding the redevelopment of the area, as well as the rehabilitation of OSH housing.

  Map 3: Delimitation of the field of study Trinitat Nova Bottom left detail of location in the municipality terminus of Barcelona. Prepared by author, compiled from mapping of the City of Barcelona The urban regeneration project in the neighbourhood proposed the demolition of 891 homes in the buildings affected by severe pathologies, to be replaced by 1045 new homes carried out in several phases. The initiative of the Neighbourhood Association, supported by several technicians, prompted in the late nineties, a participatory Community Plan with innovative sustainability criteria for the comprehensive regeneration of the area. Trinitat Nova has become an international reference for the implementation of urban environmental policies and citizen participation, and both the City Council and the Department of Environment of the Generalitat de Catalunya, have adopted some of the strategies implemented in this area, to develop successive improvement proposals in other urban areas.

  3.5 Case Study Analysis La Mina The Neighbourhood of La Mina is located in the northeastern boundary of the municipality of Barcelona, close to the sea and is separated from the town of Sant Adrià by the Besos river, the Ronda del Litoral (B-10 Motorway) and a railway line. Administratively, it belongs to the municipality of Sant Adrià de Besos, although geographically it is more understood as part of the city of Barcelona. From the start its location was complicated and marginal: not only is it an urban boundary area crossed by motorways or railways, it is also close to bothersome and polluting infrastructures (an incineration, a treatment plant and a power plant). These geographical facts generated a clear sense of isolation and an implicit movement difficulty for its residents, mostly from different substandard housing settlements located on the outskirts of the city of Barcelona.

  In the late nineties Barcelona gives green light to the "2004 Universal Forum of Cultures" and a little later other projects are carried out to transform areas near La Mina such as; the redevelopment of the end point of the Diagonal, the district 22@Barcelona, the new intermodal station at Sagrera AVE , etc. making the location of La Mina Neighbourhood no longer peripheral, a starting point to some degree of centrality enjoyment.

  La Mina emerges in 1969, becoming part of the last period of polygonal housing estate construction for shanty town absorption, promoted by the PMV; a construction operation of more than 2000 homes hosting approximately 15,000 inhabitants in an area with a total surface of 17.5 hectares . From origination, the residents’ situation was dramatic, the neighbourhood dragged with it social problems from its genesis, that worsened due to drug trafficking and vandalism, stigmatizing the neighbourhood and causing its exclusion and isolation. Continued youth unemployment was 30-40%, aggravated by a generalized low level of education. The illiteracy rate of 1996 was 9.63%, only 15% completed secondary school and only 7.5% had an additional degree. More than half of the inhabitants of La Mina are young people under the age of 35 years. They are the children of the first residents of the neighbourhood, who still live in their parents’ home because they have financial difficulties that impedes their emancipation .

  Map 4: Delimitation study of La Mina area In magenta dashed line; the limit of PERM, continuous blue line; Ronda del Litoral, and blue dashed line the railway. Prepared by author, compiled from the mapping of the metropolitan area of Barcelona and data PERM In addressing the urban regeneration project in the Neighbourhood of La Mina and according to the diagnosis, three fields of action opened: the social, the constructive, and the urban. The proposal, the "Plan Especial de Reordenación y Mejora del barrio de La Mina" (PERM) (Eng., Special Plan of Reorganisation and Improvement of the Neighbourhood of La Mina), is run by Jornet-Llop-Pastor SCP architects, definitively approved in 2002 and prorogated in 2010 until 2015. To carry it out, there is a management and coordination body, the Consortium of the Neighbourhood of La Mina, which brings together different institutions (Generalitat of Catalonia, City of Sant Adrià de Besos, Barcelona City Council and Barcelona Community Diputation).

  The interventions that identify the PERM, according to the document itself, can be summarized in three basic points: • Centrality: it gives the neighbourhood places where mass demonstrations can be carried out, spaces of connection, where the city gains its expression.

  • Diversity. On three levels: social, concerning the composition of the people living in the neighbourhood; physical, regarding the definition of spaces, architecture and housing typologies; and economic, in the diversification of productive activities that can be undertaken.

  • Exchange: to avoid social disruption and isolation. In this regard connectivity to the outside of the neighbourhood is promoted, additionally, attractive elements are arranged to generate relationship flows between the neighbourhood and the rest of the city.

  4. Matrix criteria 4.1 Selection criteria. Grouping in three axes Urban regeneration committed to improving urban sustainability will therefore have to rely on the three pillars set by ICLEI: The environmental axis, the social axis, and the economic axis (see Anexo section 1.2). The three are interdependent and the sustainability goal will not be attainable if action is only partial and with some of the above. All three are necessary and moreover, interdependent. As explained in the methodology (see Anexo section 2.2), the proposed final matrix is the result of an iterative process that feeds from the analysis of practical case studies, the review of specialised bibliography, and the discussion with others researchers and specialists in the field of research.

  Following, very briefly summarised, are three stages of the proposed matrix iteration throughout the research process:

  • The initial matrix, parts from the methodological base of "Ecological urban regeneration" proposed by Eckhart Hahn, born from the process of achieved transformation projects in the Neighbourhood of Kreuzberg in Berlin in the late eighties, and still a pioneering model for urban recycling operations. Hahn's work is not only one of the first studies in the field of urban ecology, but the developed proposals transcend built spaces to influence, especially, social and political-economic aspects of urban regeneration. His focus, like the proposal of this research is integral, considering the three areas: environmental, social, and economic.

  • The intermediate matrix, product of an iteration fueled by consulting other relevant sources in the field of sustainability and regeneration of neighbourhoods; and on the analysis of case studies. In this first iteration of the matrix, starting point criteria are modified, and the structure enriches from not only theoretical material query, but also from the analysis of more case studies and discussions with specialists. From this moment on the investigation into the interdependence and cross-cutting criteria belonging to the three axes begins.

  • Final matrix proposal, last research distillation result process contains a maximum of six criteria per axis, optimizing the use and application of the matrix. Each of these criteria, are sometimes divided into different levels, proposing reference values, attributes and properties for qualifying and/or quantifying each of them. A brief summary of all of them in Table 3. Further on, one of the identified criteria is presented, in this case pertaining to the economic axis, announcing the interrelations and synergies of the other criteria of the matrix, detailing as well the assessment means, as an example.

  4.2 Summary Matrix Environmental Axis Social Axis Economic Axis Criteria | Indicator Brief definition Quantification | Qualification Criteria | Indicator Brief definition Quantification | Qualification Criteria | Indicator Brief definition Quantification | Qualification 1. Urban Cycles, Biomimicry 1.1 Water cycle: consumption, water recycling Reducing consumption by 30% 1. Governance and leadership of the public Public leadership planning of the of the urban transformation actions with empowerment for citizens Neighbourhood Offices 1. Eco-effectiveness and minimisation of waste Invest the resources rationally (maximum improvement with minimum consumption of energy and resources) empty housing: max. 2% Saving measures and recycling water 1.2 Energy cycle: saving, renewable energy integration New construction <15 kWh / (m² year) Minimize footprint Rehabilitation <25 kWh / (m² year) new building <15 kWh / m²a rehabilitation <25 kWh / m² a Incorporating renewable energy 1.3 Materials cycle Materials max. 300 Kg CO2 / m² building components durability vs. rehabilitation opportunity 2. Urban diversity 2.1 Diversity of uses and activities that allow easy daily life in the immediate environment min 20% buildable to other uses 2. Maintaining the existing population That improvement actions in the urban fabric of the neighbourhood do not involve expulsion of neighbours living there 70-80% stay of of the population after 10 years 2. Legal Framework and Program Management Innovation in the adaptation of available tools or programmes Creating public subsidy funds 20% min - 80% max predominant housing 2.2 Diversity of spaces, architecture and building typologies new building, min 20% other typologies Implementation of self-help programmes min. 10% social rent housing Support programmes for long term urban regeneration existing building, actions for diversity Implementation of specific measures for the maintenance of the population 2.3 Diversity of people (age, income, culture ...) min 20% - max 80% free or protected housing Office for programme management and assistance 10% social rent housing 3. Sustainable Mobility and Accessibility 3.1 Prioritization of public transport or non-motorized variety of options, alternative to car use calmed traffic measures 3. Social cohesion Promote mixing of incomes, cultures, ages, etc. and promote their integration 30% min. protected housing (10% social rent housing.) - max. 80% 3. Generation of green jobs Jobs that help reduce energy consumption, raw materials and water, helping to decarbonise the economy Training programmes related to the sustainable regeneration of the neighbourhood, especially aimed at resident unemployed population 50% sup. car dedicated roads 50% to other uses building fronts <100m Bus, bikes 300-600 m Metro 600 – 900 m Suburban 900 – 1200 m City Equipment: Range of 1km max. 3km 3.2 Proximity of facilities to housing, accessibility City facilities: 1km action range (max 3 km) Neighbourhood equipment: Action range of 400 m District equipment: action range 400m Spaces and programmes promoting associations 4. Urban equitable distribution Decentralization of equipment and services for all neighbourhoods of the city to have comparable quality City equipment: 1 Km action range (max. 3 Km) or inclusion in the area itself 4. Participation Action in which all actors involved in the urban regeneration process intervene in it with decision-making capacity Neighbourhood Council Social housing 20% owned 10% + social rent equivalent public space quality throughout the city Regeneration Committee 5. Urban density residential The urban residential density in urban areas quantifies the idea of proximity of residents in a particular area 100-160 housing/ ha 5. Security Objective and subjective personal condition of being free of violence or threat Building height <6 floors 50% max. street car section Residential street width 9-10 m Pavement stay min 5 m Traffic calming measures housing and urban uses oriented to the street 6 housing per vertical nucleus Formal quality space Maintenance 6. Urban green Counteracting the heat island effect, improve air quality, urban biodiversity support, etc SBI 0,3-0,6 6. Public open spaces 6.1 Urban green areas as an indicator of quality of life Green: 15 - 20m² per inhabitant Quality of public space: vitality, readability, connectivity, comfort, safety 6.2 Public open space and social well-being Public open space-city: 1 Km action range (max. 3 Km) Public open space-district: action range 400m Table 3: Matrix summary of the proposed criteria organised in the three axes of sustainability Prepared by author 4.3 Developing one criterion of the matrix 4.3.1 Eco-effectiveness and minimisation of waste Definition "Eco-efficiency means working on the right things -on the products, the services and the correct systems- by undertaking fundamental redesign and reconstruction, rather than limiting ourselves to incremental changes to make the wrong things less bad. " This means giving way now to a new paradigm that allows a different approach to the current problems to be able to develop effective and sustainable solutions. We could illustrate this idea with the following example: currently we generate huge amounts of waste. A strategy based solely on efficiency, would provide a solution to the problem, a system where the amount of waste generated is reduced, certainly an improvement; but the paradigm shift that eco-effectiveness pursues, would, however, lead to a system that does not produce any waste.

  Urban regeneration is an appropriate strategy in the fight against the waste of resources and energy. With it the demand for new land use is reduced, solving the demand for housing on new surfaces. The weight of the regeneration of the built fabric, with respect to the activity in the building sector varies from some areas to others. In the European context this assumed weight reaches 40% on average, although in some countries it is above that, as is the case in Germany with 60% and other countries standing below. In Spain, for example, the weight of rehabilitation only represents 24% of the activity of the sector .

  Wasting, reported by Campos Venuti, linked to the objectives of municipalities of oversized population growth, not only unnecessarily consumes surface (so valuable), but also built heritage, which rather than being revamped, is abandoned and ends (in some cases) being demolished to rebuild once again, implying speculation encouragement and also involving waste of credit.

  Sustainable urban regeneration represents a decisive strategy for the fight against waste and involves at least three types of cost savings: • Savings in the payment of fees and/or fines for CO2 emissions. As we know, Spain is far from the fulfillment of the Kyoto protocol and should be purchasing, each year, emission rights for more than 100 million tons of CO2 the equivalent translates into monetary cost that could reach more than 3,500 million euros.

  • Savings from decreased energy expenditure that could result in savings of 169,500 million euros.

  • Savings from reduced spending on unemployment, estimated at 192,000 million euros for the period 2010-2050 .

  Regarding wasting linked to the area of housing, primary use of the neighbourhoods in the city, are the following facts. On the one hand, the value of the home exceeds its value as a means of seeking shelter and livability. "The equity value of housing prevails over its use value and tends to standardization on a small set of distributive typologies." This generates an inadequate housing supply number relative to demand and typology, concerning the need to adapt to new lifestyles and changes in society. "This inadequacy generates waste of spaces and resources in some cases and in others, problems of access to housing or substandard housing, relevant to individual income." But sustainable urban regeneration makes possible benefits beyond the financial and environmental point of view that should be valued and taken into account. A successful sustainable urban regeneration project is a major benefit to citizens, though not easy to quantify in euros. "In plannings’ balance sheets what is measured is the production of: housing, roads, public buildings. In no case is the quality of life, integration of citizens in their environment, reduction of displacement, participation in social tasks, or the weighted distribution of facilities to serve the public, measured." However, it escapes no one that a safer urban environment, healthier, cleaner, with less pollution, etc., has advantages that also affect the health and wellbeing of citizens, which simultaneously directly affects economic aspects. In fact, the ultimate goal of economic activity should not be competitiveness and economic efficiency, but improving the quality of life of people.

  Mainstreaming of Eco-effectiveness and minimisation of waste with other criteria Environmental axis Social axis Economic axis Urban Cycles Biomimicry Governance and leadership of the public Eco-effectiveness and minimisation of waste Urban diversity Maintaining the existing population Legal Framework and Programme Management Sustainable Mobility and Accessibility Social cohesion Generation of green jobs Urban equitable distribution Participation Urban residential density Security Urban green Public open space Table 4: Mainstreaming of Eco-effectiveness and minimisation of waste with other criteria of the proposed matrix Colour highlighted relationships and synergies between criteria. The greater the inwardly involvement between criteria, the more intense the colour. Prepared by author Table 4 above, gathers in summary the mainstreaming approach of this criteria with all the rest in the matrix. In this particular case, as stated later on in the research work conclusions, this criterion can be considered one of the basic principles of sustainable regeneration of neighbourhoods because of its mainstreaming and influence on other criteria and indicators of the proposed matrix. Next, and in brief summary, a description of this relationship with a criterion of each axis.

  1.- With urban diversity Urban spaces that count on a variety of uses and activities, of typologies and people, are urban spaces of great quality of life for citizens, which operate throughout the day by optimally making use of existing infrastructure and buildings. Moreover, the diversity also has an impact on the occupancy of houses and thus, a positive impact on the amortization of investments.

  "The creation of diverse neighbourhoods from a social point of view, with an appropriate mix of uses and offering a high quality of life, allows for the reduction of the number of empty homes and commercial establishments." 2.- With governance and leadership of what is public The governance and leadership of what is public are key to minimizing the waste and in the development of cooperation agreements between the various agents (of public and private character) who are involved in the urban regeneration processes. In particular, the administration (of what is public) has a very important role in the fight against wasting. They are responsible for ensuring compliance with the regulations governing the quality of buildings, materials, planning, etc. influencing the resulting habitability and the degree of sustainability of the actions.

  3.- With green jobs Sustainable urban regeneration offers good prospects for generating green employment in the fight against the waste of resources and energy. The rehabilitation of the Spanish neighbourhoods in particular, is a clear opportunity for restructuring the construction sector, currently in crisis. According to "the conversion plans of the urban area of Playa de Palma, the demand for labor in terms of the investment can be placed in 25 direct jobs and 38 indirect jobs for every million euros invested in the sector, assuming the occupation at approximately 1.2 million people according to the financial investment of one year, an amount that is equivalent to 27% of the unemployed registered in the fourth quarter of 2009, according to INE." Identification of values for the quantification and qualification of the Eco-effectiveness and minimisation of waste In this section reference values are identified for Eco-effectiveness and minimisation of waste in the context of sustainable urban regeneration, focusing on the aspect of housing in two scales: The scale of the neighbourhood and the building scale.

  For the first level; the scale of the neighbourhood, the "empty housing" indicator is proposed as a measure of proper execution or not of the residential demand, the ultimate reason for neighbourhoods in the city, defined as "the amount, according to the total, of family housing, not dilapidated or to be used as primary or secondary residence, and that at census time is considered uninhabited." Excess vacant housing means there is an unmet need for accommodation, which advocates a waste or poor use of the building, materials, resources and energy. As a benchmark, we take 2%. Above this value a waste of the existing building would be confirmed. In Spain, in 2001, unoccupied housing represented 9% in total, value above the average in the European environment (6.8%) and well above countries like United Kingdom (4.8%), Germany (3.6%) and the Netherlands (2.3%).

  On this scale a recommendation is also set forth, a check-list item; land consumption. Sustainable urban regeneration contributes to improved habitability, and in many cases also to meet housing deficit within the existing urban area without forcing the expansion of the city and the consumption of new land. In this sense, and in the case of building new structures in the area of the neighbourhood, it must be adequately justified, and not responding to pressure from players seeking a purely economic benefit.

  There are several authors that emphasize the need to assess the capacity of the existing city and reusability of existing urban land, before embarking on an urban plan on new ground. In the UK this is common practice and as such is set down in legislation, giving priority to intervention of "brownfields" opposed to action on "greenfields", the latter, recorded with a tax to subsidize urban regeneration projects.

  For the second level; the building scale, recommendations for execution of rehabilitation energy projects of buildings are proposed, minimizing the waste of energy and resources. The construction and maintenance of the built heritage represent about a fifth of the total consumption of materials. For this reason, special attention should be paid to actions taken on the building, in the effort to reduce long-term expenses, since the useful life of the building is long and entails very high energy costs. There should be an investment that allows compliance with the greater demand for thermal insulation, for example, to contribute to greater savings in energy use (in this case heating/cooling) for future years.

  As stated in the criteria Urban Cycles and Biomimicry, a standard for energy rehabilitation of heating demand ≤ 25 kWh/(m2a) is proposed, and special emphasis is made on this criterion pertaining to the economic axis, to the care that must be undertaken when faced with energy rehabilitation projects, since if it is not possible to optimize the improvement, the waste of energy and materials will continue for a very long period of time. The maximum value for primary energy demand in the case of new construction of 15 kWh/(m²a) is also readdressed, as proposed in the standard of urban cycles.

  It takes into consideration that despite being the most appropriate, not always is there sufficient budget to achieve that standard at once. For these cases, it is recommended to undertake a phased rehabilitation or by building elements.

  The components of a building have a variable durability depending on which element is concerned. Its point of exhaustion or recommended change time, is not in all instances the same. For instance; the durability of a plaster facade is estimated at about 70 years, but a renewal of the finish every 55 years is suggested. In the case of windows (in buildings of the 50s and 60s) a change of the woodwork at 30 years is recommended, although the durability thereof is estimated at about 80 years. In fact, the -decision-intervene-moment- on a building and how to act, is critical to minimize waste and ensure optimum use of resources and energy.

  The measures for improving the thermal conditioning of buildings, are particularly economically profitable when linked to rehabilitation measures, however, independent of the energy improvement. For example, an improvement in the external facade insulation linked to the cement render of the facade, is optimally profitable, as part of the cost of scaffolding, removing the plaster damaged works, application of new plaster, etc. These were to be performed independently of the energy improvement and could be, so to say, a "stolen" cost thereof. For this reason, it is necessary to assess whether change/rehabilitation action in a building can be incorporated into an energy effective improvement. Otherwise the opportunity to be resubmitted is lost and will not present itself again until the depletion of the new components.

    5. Conclusions The city must adapt to environmental, social and economic demands to be sustainable and thus ensure the prospects of present and future citizens. In this context, urban sustainable regeneration is a key strategy for improving the living conditions of the inhabitants of the cities, to make reasonable use of energy and natural resources. In the particular case of Spain, tradition in the field of urban recycling is not as deeply ingrained as in other countries at European level, such as Germany, and yet it has one of the most suitable urban climate curb change policies; which constitutes an opportunity for economic recovery for the country, at moment paralyzed because of a severe economic crisis.

  1. Sustainable urban regeneration must respond to the three pillars of sustainability Urban regeneration with a commitment to improved sustainability must necessarily be based on the three pillars of sustainability set by ICLEI. That is, it should be supported simultaneously in the axes: environmental, social, and economic. The three are unavoidable and interdependent, so the goal of sustainability will not be attained if it is acted upon only partially and in some of the axes.

  So far, the prevailing economic and productive system goes beyond the limits of the planet and therefore it is necessary to act upon reduction of supply, adapt the human ecosystem to natural ecosystems, act on the demand from a self-restraint standpoint, etc., all these measures require a review of the social and of course the economic, at a local and global scale. It is not possible to separate society and the environment, nor, economy and nature.

  Sustainability in the city as a contribution to global sustainability, should not only address environmental issues related to the built substance. Cities are what they are, thanks to the social fabric that composes them, and from their genesis the economy defines their morphology, function and what they become. Then, necessarily, urban regeneration, like planetary sustainability, must act in these three areas to achieve effective change and achieve the goal of not crossing planetary boundaries.

  2. The matrix of criteria proposed proves the mainstreaming of the three axes of sustainability The matrix of criteria proposed for the regeneration of sustainable neighbourhoods, demonstrates the interdependence between axes and the need for action in all three at once. Each of the selected criteria have transverse, multiplier and synergistic effects, for each of the three axes (environmental, social and economic), as discussed in detail in Chapter 4, Matrix Criteria. Proof of this is that some of the values identified in reference to a criterion of a particular axis may also coincide with the quantification/qualification of another aspect, belonging to another axis. For instance; the reference value for the proximity of the facilities to the housing, criterion Sustainable Mobility and Accessibility pertaining to the Environmental Axis: "Neighbourhood facilities should be placed in a maximum range of 400m from the housing", also involved in the quantification of Social Cohesion criterion, part of the Social Axis. Both criteria also exert an important influence on others, such as eco-efficiency and minimizing waste (economic axis), participation (social axis) and urban diversity (environmental axis).

  3. The case studies present different aspects, however, also they have important common elements and strategies that can be extrapolated to other contexts The selected case studies, although presenting differences in many respects, are exemplary cases of transformation of the existing city, from where implementable strategies can be drawn into other contexts. The four test cases are chosen in two cities, Berlin and Barcelona, both key to study urban sustainable regeneration. In all of them, action transcends over improvement of the environmental performance of the built matter, for patterns of urban transformations of the social and economic.

  Although the four cases between them have very different aspects, such as; the edifice morphology, a predominant type of regime trend, the moment in which the projects are developed, and the cultural background and idiosyncrasies of the neighbours is different; there are numerous common aspects in the socioeconomic situation of the inhabitants, the genesis of urban areas, and a baseline with problems that transcend the building deficiencies, to name a few, that makes them comparable. The four case studies count on, for example, a certain stigma before the start of the transformation process, the neighbours who live in the area suffer from similar socioeconomic problems (high unemployment, low education levels), the position of the neighbourhoods is originally peripheric, but with the passage of time takes on a relatively central location, etc. All four cases count on a will to jointly achieve sustainability, improving the quality of life and well-being of the residents of these urban areas.

  Despite the specifics of each case, common aspects have been identified that can be generalisable in other contexts, at least within Europe, enabling the implementation of strategies that have worked successfully, detected by analysing case studies, which can be helpful for the future development of urban regeneration projects in other geographical areas with similar, starting point social and economic situations.

  4. The contributions of the methodology used in research 4.1. The methodology of the research proves its validity by means of obtaining the objective, the criteria matrix, and provides three areas of main interest. First, the dynamic focus on constant retroactive feedback on the process of drawing up the matrix, distilling the criteria and reference values organised in the three axes of sustainability, both from the theoretical investigations, as from the analysis of four case studies; identifying aspects applicable in other contexts, such as: the Soil Biotic Index (Biotopflächenfaktor) used in Berlin to promote urban greens with a better environmental performance, or the formation of a Neighbourhood Council (implemented in both Kreuzberg, and Trinitat Nova) as a body that promotes the participation of residents in the process of transformation of the neighbourhood. From this analysis, in contrast with the existing theoretical framework on sustainable urban regeneration, and case studies exemplary of urban regeneration, is it allowable to extract various strategies and generalisable results, universally valid, that can be applied, at least, in the process of improving neighbourhoods in European cities.

  4.2. The second contribution is made up from the matrix of the criteria and values of reference, as proposed; as it offers possibilities of objectification and is specifically designed for the regeneration processes. The attempt to seek a quantifiable reality is useful not only for understanding the interventions, but also in the decision making processes, both for politicians, technicians and the general public. This redounds in a better arbitration of the participatory process, by providing a guiding framework and reference for fruitful debate, largely responsible for the success of urban regeneration processes, something somewhat novel, although publications relating to use of indicators in the field of urbanism are abundant.

  4.3. The third input constitutes the possible standardization of information by which the comparison of different experiences is made possible through the matrix of criteria. Choosing to work with a matrix that meets criteria and indicators as a tool to facilitate the organization of information, comparison and evaluation of different actual cases and performed in various geographic areas, resembles the idea of "Grille CIAM" prepared by Le Corbusier with the ASCORAL. The "grille" is proposed as a tool (as a grid) applied to urban planning and modern architecture, useful for analysis, synthesis, presentation and reading of highly diverse experiences that can result complex and difficult to compare, carried out in different cities. The proposed matrix in this research allows the organization of information, setting categories that establish an order, allowing a selective look for a directed assessment onto relevant addressed aspects, in this case, applied to sustainable urban regeneration.

  5. The democratization of the use of criteria and indicators for the proposed matrix, is a medium that promotes the success of sustainable urban transformation processes The matrix is not only aimed at professionals responsible for developing specific projects, it is also intended for use by administration staff that manage action, and for those affected by regeneration plans, facilitating their participation in the process. This participation, understood as active and direct, alongside government administrations with responsibility in the decision-making processes. From the case analysis it becomes evident how the direct participation of residents with public administrations in the processes of decision-making, implementation, financing (to a certain extent) and the subsequent maintenance of facilities or green areas, have been a true enrichment to the complex processes of recovery of degraded and/or obsolete areas.

  6. The use of indicators is not the only way, nor is it always the most appropriate, for the evaluation and understanding of the reality. Quantifiable criteria and strategies are also helpful At the beginning of the investigation work, the fabrication of the matrix, relying only on indicators to quantify reality, configuring a use-tool, similar to those used by the certification systems, was proposed. But in the process and analysis and development of the work it was ascertained that there are also criteria, not necessarily quantifiable with a numerical value, which likewise, help to understand the reality and-or non-suitability of the process. Choosing to only work with indicators entails some complications in the handling and representation choice, to measure and monitor the interdependence between the urban system and the planetary natural resources. Besides presenting limitations and disadvantages, such as the complexity of some of them and the prodigious contribution of statistical information necessary, which could hinder its use.

  The criteria contribute to a qualitative assessment of reality and not necessarily quantitative, but are very relevant in the development of urban regeneration projects or during the decision-making process. In fact, in several tools destined for urban design use, indicators are most commonly used. Moreover, the matrix is proposed as a simple, easy to understand and use, but also effective way to discard complex indicators, which would hinder its use; incorporating criteria in its place, also effective and more flexible.

  7. The criteria matrix proposal constitutes a support, especially in urban contexts with low recycling tradition, that promotes sustainable urban regeneration The development processes of regeneration of sustainable neighbourhoods is a task that often can not be carried out following a unique pattern; rigid and continuous for all cases; since each neighbourhood, each context, counts on specific circumstances and problems that are interrelated in a certain way. But on the other hand, the lack of an experimental trajectory in sustainable regeneration processes in neighbourhoods, as occurs, for example, in the context of Spanish cities, makes proposing a tool to facilitate this work become necessary. Providing a matrix of criteria, created especially for the application in the context of urban regeneration, with the aforementioned level of flexibility that makes evident the interrelations between the fields of action, and provides guidance in terms of numerical values on issues of a more technical concern, is offered as a beneficial first step towards sustainably transforming troubled neighbourhoods.

  8. Three of the criteria identified in the matrix, can be considered principles of sustainable urban regeneration Closing urban cycles as occurs in natural ecosystems, biomimicry, (environmental axis); a governance that makes new avenues possible for the development of urban policies along with the leadership of the public over the interests of private actors (social axis); Eco-effectiveness that promotes focused changes, no longer in a palliative approach, but seeking for real solutions for sustainability in line with the minimisation of waste promulgated by Campos Venuti, that limits unnecessary consumption (economic axis); these criteria are identified and as such listed in the proposed matrix, but can also be considered as principles for sustainable urban regeneration. Their mainstreaming and involvement among themselves, and, with the other criteria of the matrix, makes them become a kind of supra-criteria, laws or rules of fundamental importance to address sustainable urban regeneration.

  9. The creation of a public subsidy fund for sustainable urban regeneration is necessary The current "Act of rehabilitation, regeneration and urban renewal" in Spain, although a decisive step to boost sustainable urban regeneration, provides no economic fund to promote urban transformation processes as in the case of the Neighbourhoods Act of Catalonia, or funds and funding programmes in Germany. These funds are of radical importance to enable actions of urban improvement. As outlined in the development of the research work, sustainable urban regeneration is defined by the experts group on urban environment of the European Union as the "the inversion process of economic, physical and social decline of the existing city, where the decline has come to the point where market forces cannot overcome it alone." The EU panel implicitly therefore supports this idea.

  In addition to enabling specific actions of regeneration, a grant fund would allow the public administration to take control of the operations and lead the process with an advantageous position with regard to private actors, who can also intervene in these processes. Although in principle this proposal, for the particular case of Spain, may seem little in keeping with the current economic crisis; it is not absolutely so. According to various consulted studies, urban regeneration can mean a revival of the labor market and improvement, with a positive balance in favour of the country’s economy.

  10. Including maximum and minimum values of social housing and rental housing, fosters urban equity, diversity and social cohesion In regulating maximum and minimum values of social housing in the underserved city neighbourhoods, the social balance is favored, avoiding segregation or duality of cities. Promoting diversity in tenure (rent/proprietary) also acts in favor of a social mix, the first step in building socially cohesive cities. The balanced distribution of social housing in all urban areas acts as an equity improvement in all of its areas, minimizing stigmatization or segregation processes, as was the case in the Neighbourhood of La Mina, in which all housing before the transformation process was social.

  In the particular case of Spain, a unique phenomenon occurs. Despite the massive housing production in recent years, access to housing for some sectors of society was not favored (even before the crisis) because credit was not attained. At the same time, there is a poor rental housing offer, and nevertheless, many remain empty. Currently, following the economic crisis, this situation is being aggravated by the evictions, which severely accentuate the problem of access to housing for many families. The current Spanish legal framework governing the processes of urban regeneration, does not set a minimum reserve for subsidized housing or social rental prices that allow access to housing for people of lower income. This situation does not solve the housing problem, or act on behalf of diverse cities and social cohesiveness, aspects relevant to achieving sustainable cities.

  11. Urban regeneration should be considered from municipal planning Urban regeneration should be managed from municipal planning, at least for three significant reasons:

  11.1. Improvement actions in city neighbourhoods should be projects coordinated with logic and following a temporal strategy that can only be conceived from the municipal level. In this way, action will take place at the right time and in the right place, in an orderly and planned way, minimizing the waste of economic resources, natural resources and energy. Regeneration of neighbourhoods should therefore have, a short-, medium- and long-term plan, designed parting from the consideration of the city as a whole. Municipal planning allows adequate programming of interventions, ensuring a logical sequence of actions, contrary to the disorder that may be posed by the single procurement of the interests of a private sector such as real estate.

  11.2. Sustainable neighbourhood regeneration must be a strategy that is not limited to a single urban area, but it should be an action plan on a larger scale: the entire city. As for example in Germany. Since 2002 there are two programmes (due to the division of the country) Stadtumbau West und Ost, for the cities of the former West and East Germany, dealing with the regeneration of neighbourhoods, awarding each year financial resources to act on the previously identified areas.

  11.3. The urban regeneration of neighbourhoods has to be done from municipal planning, as well as among other reasons, for an urban equitable distribution of facilities, the quality of public spaces, the uses of the more prestigious and less valued, etc. (See following conclusion).

  12. Urban equitable distribution as mitigation strategy of speculative processes of gentrification Precisely, urban equitable distribution promotes a balanced and cohesive city in which all neighbourhoods have a comparable urban quality, for which exaggerated housing price differences, dependent on location, are avoided, thereby decreasing the favoring of speculative stocks. Therefore, if all parts of the city count on an equivalent quality, it will be more difficult for the phenomena of gentrification to be produced, which expels the resident population, this, occurring due to price increase following processes of urban improvement, which residents cannot cope with.

  The origin of most social problems in cities is caused by spatial segregation of social groups, caused, as we know, by the state of affairs of the ground rent and housing. Real estate prices are not homogeneous, but rely on centrality, the type of localized services in urban areas, the urban quality of the area, etc. A house of the same quality does not have the same value, this depends largely on location. In so, the people with more money have more choice than those that have less. As David Harvey explained in his book "Social Justice and the City". Unequal urban quality, encouraged by urban rental prices acts as a filter that allows some groups more freedom of choice in the use of urban spaces, while restricting the mobility and place of residence of others.

  Acting on the city as a whole, and looking for the balance of its neighbourhoods, action is taken on price balance, and the geographic and social integration of all neighbourhoods in the city as a whole.

  13. The energy rehabilitation of the building has to ensure maximum effectiveness and therefore must meet the most exacting energy saving standards Taking action on the existing building by looking for improvement in energy consumption, presupposes a consumption of resources and materials that will be applied from the beginning of the eco-efficiency and waste minimisation. The actions taken will condition the consumption and behavior of the building in the next thirty, or even, fifty years. Therefore, this research proposes meeting the highest level of requirements for the building, Passivhaus standard , tested and applied worldwide, thus, avoiding waste in the consumption of energy and resources.

  To address the processes of urban improvement, as discussed before, it is necessary to create a fund of public subsidy that on one hand, enables starting point investments and on the other, ensures leadership and decision-making power of the public administration. In addition to enabling self-help measures, in which the residents themselves can collaborate physically, enabling actions to improve the efficiency of the building.

  Without a doubt, the inclusion of renewable energy production systems in the area of an existing building is also an important and necessary piece to be included in the actions on the building, but should be incorporated after a reduction of energy consumption, not before.

  14. The implementation of measures on saving water consumption is necessary especially in areas at risk of desertification So far, in the case of Spain, there is no regulation on the rules about the behavior of the building in relation to water consumption. Nevertheless water is a precious resource and in some areas, a scarce resource that plays an important role in the future of cities, especially in areas at risk of desertification. For example, in Spain 35% of the land area has a high risk of desertification, and yet, water use is not regulated by any rules of construction; without establishing any minimum measure or minimum recycling and water saving standard for housing, a possible reduction of consumption by more than 30% is however estimated.

  15. Urban regeneration can be a means for stimulating social cohesion Joint work and the achievement of common goals encourage a greater sense of community enthusiasm coming from the neighbours, who feel they can change things. Somehow, these common interests, that are fought for together, serve to remove the economic, social or ideological differences from the start, making the feeling of belonging to a shared project prevail. All this helps to consolidate democratic credibility, extending it into all aspects of society.

  16. Participation in processes of urban regeneration improves the neighbourhood identity, the maintenance of spaces, and steers a learning experience that seeks to change the paradigm of sustainability 16.1. It is known that the neighbours feel more connected to a space that they have helped create. Participation allows proposals to be assessed and tuned before being adopted, which in turn results in better use of public resources and a greater dynamism in the process, considering that dialogue can avoid wasted time in conflicts. In addition, the final results will be more suitable, as the final recipients of the intervention (the neighbours) are a firsthand source of knowledge and wisdom. Lastly, it is fitting to expect that they will monitor and maintain it better, reducing the likelihood of vandalism, neglect and subsequent need of replacement.

  16.2. Including the elderly people, children and youth as an active part of various urban improvement projects has numerous positive effects. The implementation and maintenance of open spaces and urban edible gardens, animal care, participation in the construction of playgrounds, to give several examples, are all experiences that not only play an important educational role in making self-evident and palpable the need to care for the environment, the understanding of natural processes, the importance of collaboration and the value of public resources, but also contributes to the maintenance of spaces and the survival of neighbourhood initiatives, improves urban quality and the range of activities in the area of the neighbourhood, while promoting the associative fabric.

  17. Urban regeneration should seek the strengthening of associations The associative fabric has been instrumental in many of the analyzed demands for improving the spaces. It has served to drive demands and actions (many of them pressing) that probably, without it, would have been impossible. They have also served, and serve, to address groups that are at risk of social exclusion, promoting inclusion and strengthening vulnerabilities through training and support networks, etc.

  The implementation of self-help programmes can be an enforcement mechanism of great value in urban regeneration projects. It implies a way of channeling cooperative and voluntary work that can fill investment gaps (public or private). It is intended for construction (directed self-construction), but can also be used for repairing bicycles, wood construction workshops, gardening, etc. In addition to enabling the improvement of spaces and services, it allows for greater identification with projects and responsibilities. To which must be added, as well, that lower-income neighbours can remain in the area (in the cases of housing rehabilitation), favoring a mixed social structure of great urban value.

  Performance, for example, of the self-help programmes for construction-rehabilitation, are based on compensating the investment needed for rehabilitation, carried out by a construction company, with the neighbours’ own work. In the specific case of Kreuzberg, in 1981, a maximum grant of approximately 800 DM (400 €) per square meter, which represents 80% of the total renovation work costs to the building, is established, in exchange, neighbours physical labour is required, valued at 20%. (In practice, this percentage is exceeded in many occasions, according to STERN himself).

  18. Sustainable neighbourhood regeneration should promote job creation (in some cases, the so-called "green jobs") within the action scope themselves Beyond the immediate benefits of finding employment for those that have been without a job for a certain period, something valuable in itself, hiring programs for the unemployed neighbours to implement urban improvement tasks can be assumed as a break in the circle of marginalization (social problems, vulnerability, etc.) which can be reached after a long periods in jobless situations. It is known that long-term unemployment becomes a handicap for finding work, a vicious cycle, from which a one year contract can help break the cycle. Inciding on this aspect, is again, the matter of social cohesion, of permanence of neighbours in the neighbourhood, to improve the living conditions of specific groups and, by extension, improving the daily coexistence of the neighbourhood.

  Sometimes, as detailed in the example of Helmholtzplatz (Prenzlauer Berg), the jobs created also fall within what the UNEP (United Nations Environment Programme) defined in its 2008 report as "green jobs". These are those jobs which reduce the environmental impact of companies and economic sectors, until ultimately reaching sustainable levels. Green jobs help: to reduce the consumption of energy, raw materials and water through efficiency strategies, to decarbonise the economy and reduce emissions of greenhouse gases, to reduce or avoid altogether all forms of waste and pollution, and to protect and restore ecosystems and biodiversity.

  19. Urban regeneration is an ideal framework for organising awareness and information sessions about sustainability to promote a paradigm shift The paradigm shift towards sustainability involves, as discussed throughout the research work, a transformation in the way society relates to the environment, in this specific case, applied to the improvement in performance of the existing city. And in as such, this transformation is therefore closely linked to the citizens, to their individual and cooperative actions, to their ways of life and lifestyles, their intervention, acceptance, demand and participation, in the necessary changes that will make possible more sustainable cities and neighbourhoods.

  The framework of urban regeneration provides an ideal opportunity for the organisation of seminars/workshops to raise awareness and training on sustainability, at a local level, and its implications at global scale, aimed at all stakeholders in the process. In this manner, encouraging a deeper understanding of the scope of the urban regeneration specific actions, that will influence maintenance improvements and the tangible realisation of projects, added to promoting changes in the lifestyles of the residents, that will transcend the temporality of the process and work in favour of a long-term paradigm shift.

  20. Urban regeneration processes require time, will, dialogue and negotiation In facing a possible implementation of guidelines for urban regeneration in other contexts to those studied by means of case analysis, it is worth noting that, although they are, as we have seen, complex processes that require perseverance, and the power to convince the neighbours of the value of what is public in the neighbourhood, in which it is necessary to invest time, and involvement, and even requires a certain associative base; however; does not require a large financial investment (as required by the construction of urban ex-novo areas) offering more than obvious advantages. Not only capable of improving facilities, the quality of urban spaces and green spaces, but are able to generate actions of comprehensive urban regeneration (of buildings and urban spaces and social fabrics).

  They are based on universal principles, and therefore, it is understood that they are relatively easy experiences to implement in different places, within a variety of social, economic and idiosyncratic circumstances. The key to the success of the projects is in real participation and co-responsibility of all of the stakeholders in the process. The decision-making process should be conducted in a decentralized manner and, whenever possible, self-management processes should be relied on. All parties win, neighbours gain a better quality of life, governments save investment costs, etc., and in exchange everyone must contribute volition for dialogue and negotiation power.

      21. Summary analysis of the; strengths, weaknesses, opportunities and threats of urban regeneration that are case-specific to neighbourhoods in the first level periphery of Spanish cities Strengths Opportunities • The neighbourhoods built in this period, peripheral in origin, currently enjoy, due to urban expansion, a position of relative centrality • The building typology is, in most cases, open block. So these areas often have sufficient public space (amount) • Residential density is a good starting point in most areas, with optimum estimated values ranging between 100-160 housing/ha • The building is generally less than six stories, except one or another tower building, this benefits starting value, for example to promote security in the city (see Chapter 4 Matrix Criteria) • The prevailing regime is of tenancy, which makes it easier to maintain the resident population in the area after urban regeneration. At least when compared with urban areas where the prevailing regime is renting, which is more sensitive after improvement • Although at present it may be weakened, or if it does exists at all, usually, in these neighbourhoods a capacity of neighbourhood associations and movements capable of being reactivated with urban regeneration • Most of these neighbourhoods count on certain social cohesion and with a good neighbour-identification with the urban area • The neighbourhoods built in the years 1950-1980 currently count on, as previously indicated, with a position of relative centrality. What presupposes an opportunity to achieve sustainable mobility in a non-very-expensive way. Empowerment of public transport use, bicycles and walking, is easier, than in more remote areas from the urban centre • Achieving active participation and a strengthening of network support in first level periphery neighbourhoods, presents itself with more feasibility than in areas of low density in current Spanish periphery cities • Weather conditions in Spain are not as severe as in other European latitudes. In particular, Spain has a privileged position for the use of solar renewable energy sources. Whereby the implementation of strategies for minimizing energy consumption is a possible task • Urban regeneration processes are an opportunity to improve the socioeconomic situation of the resident population through training programmes, self-construction work systems and new "green" jobs in the area, when orientated to giving priority to unemployed neighbours within the neighbourhood • Empty plots or plots where the approved projects have not taken off due to lack of funds, for example, in the first level periphery neighbourhoods of Spain, constitute a unique opportunity for self-management, by turning them, at least temporarily, into new facilities, green areas, urban gardens, etc.

  Weaknesses Threats • The neighbourhoods of the first level Spanish peripheries are primarily residential neighbourhoods with high prevalence of social housing, with little mixed use, although some of them do have a minimal commercial fabric • The quality of the original building is quite deficient regarding issues of livability, accessibility and energy • The socioeconomic situation of the neighbours does not enjoy a position of advantage, in most cases the population is considered vulnerable, and an important social mix is not common • The neighbourhoods of the first level Spanish peripheries, often do not have facilities or uses of centrality to the city, but tend to accumulate less attractive urban uses • The quality of public spaces and green areas is often poor and does not count on a hierarchisation. It also tends to have too much emphasize on car use on streets and pavements, since residential buildings do not usually have underground parking • The image and building typologies are often too homogeneous with little variety • Accessibility problems (no lift availability) in blocks of up to five stories • There is no regeneration culture and maintenance of neighbourhoods in Spain, except for specific cases • Many of the neighbourhoods of the Spanish first level peripheries were built to allocate vulnerable people, recently arrived from rural areas and often residing in substandard housing. Within the democratic period, improvement operations were carried out on some neighbourhoods and facilities, improving the quality of life in these areas. The process of expansion of the city, in turn, made part of the intermediate social strata leave the town center towards the periphery, reducing, in part, the income gap between the center and the metropolitan area. In the late nineties, population growth associated with immigration, fostered a new concentration of the most vulnerable population in the centre and first level periphery of Spanish cities. There, where prices were lower . The current economic crisis makes it difficult for many citizens to access the housing market, so the demand of the less solvent will likely focus on areas with lower prices (such as these neighbourhoods), possibly causing the exit of the more affluent population sectors, falling back onto the formation of the ghetto or of social segregation • At the same time another phenomenon is occurring in cities: the return of the more affluent strata from the periphery to the city centre. The current location of these first peripheries, is today, certainly central. So, if action upon improving the quality of housing, facilities and open spaces, in the area is revalued with the consequent rise in prices, it may eventually lead to the expulsion of current residents and start gentrification, although a property ownership circuit attenuates this risk • Problems in the built fabric of these neighbourhoods often preclude rehabilitation, advocating building substitution processes, with consequent demolitions, relocations and construction of new buildings which complicates the process and prevents the conservation of the so-called gray energy (energy worn out in its origin and that it is not necessary to use in new buildings). Although the renovation of the building on already urbanized land is always more advantageous than building on new land Table 5: SWOT Analysis for sustainable urban regeneration of neighbourhoods built from the 50s-80s in Spanish cities Conclusions for the specific case of Spain. Prepared by author