Archivo de la etiqueta: materials


Of the cases registered in our database on railway dwellings built during the study period: 19,015 dwellings and 253 developments, 94% of the dwellings and 91% of the developments were built in what we know as cities, i.e. in population centres with more than 5,000 inhabitants. This percentage drops to 68% and 60%, respectively, if we look at medium-sized and large cities (more than 50,000 inhabitants) and is even lower if we only look at large cities, with 45% and 29%, respectively, of the dwellings and developments built. In other words, the construction of railway housing in this period was a clearly urban phenomenon, typical of the period, but in which medium-sized cities also played a leading role: we must bear in mind that in many cases these were provincial capitals (Ciudad Real, León or Granada, among others) or important railway hubs (Miranda de Ebro, Alcázar de San Juan or Águilas, among others). There is, therefore, a more balanced distribution of housing, related to the characteristics and needs of the railway operation, although Madrid, Valencia, and Barcelona, in that order, account for 30% of the housing built. Sigue leyendo


From the 1940s onwards, the housing problem took on crisis proportions and threatened to affect the stability of the Franco regime. In fact, one of Franco’s first legislative measures was precisely the new housing legislation. Specifically, the Law of 19 April 1939 had two clear objectives: first, protective measures to encourage the construction of subsidised housing; and second, the creation of a regulatory department such as the National Housing Institute (INV). Sigue leyendo


We have recently published an article on the problems detected in a large part of the housing stock in our towns and cities that were built during the second half of the 20th century, when the technical standards did not contemplate any vocation for energy saving or reuse: When construction was linear. Analysis of the energy sustainability of social housing in Spain (1939-1989). Los objetivos y conclusiones de dicha publicación os la incluimos a continuación. Sigue leyendo


At the end of the 1950s, with the development of capitalism, there was an unimaginable growth of large cities and therefore the need to generate mass housing. The 1960s was the decade of housing estates inspired by the most perverse functionalism, works carried out by the Ministry of Housing, by the Obra Sindical del Hogar (OSH) or subsidised housing such as that of the railway workers, which had no other aim than to provide cheap accommodation for the labour force that was arriving in the cities in waves (Grau, 1993). In the case of railway housing, this second period, 1965-1989, is characterised by workers’ cooperatives as the promoters of their housing.

Unlike the first period analysed in a previous entry, the substantial socio-economic change occurring in this second period gives importance to regulations, especially those of an urban planning nature and to the design and quality of social housing, as the only limit to speculation, and, although we can detect evolution with respect to the regulations existing in the previous period, their drafting is far removed from the theoretical studies of sociologists and architects, being basically driven by two motors: Increases in the social pressure of the user and the demand of capital for higher and higher capital gains. The result is poor, rigid and unimaginative regulations which, on a technical level, encourage the repetition of design solutions and, therefore, of construction solutions which become standards where cost and profitability are the basic premises (Paricio Ansuátegui, 1973). Sigue leyendo


In order to deal with the subject of this entry, it is necessary to distinguish between two periods: the first, between 1949 and 1965, when practically all the housing promoted by RENFE was built, and the second, between 1965 and 1989, when the main promoter group was made up of the cooperatives formed by railway workers. This distinction derives from the technical regulatory context, which prescribed construction solutions and materials in the housing project, and also with regard to the availability of materials to carry out the construction.

In this sense, for the dwellings of the first period, two technical regulations were in force: at first, the Order of 29 February 1944 (BOE, no. 61, 1 March 1944) was approved, which determined the minimum hygienic conditions that dwellings had to meet, drawn up at the proposal of the Local Health Commission and which basically consisted of a compendium of 14 precepts which did not deal with the issue of foundations and structures, However, it did require, for dwellings on ground floors, or in those that were allowed below street level, to guarantee waterproofing or insulation against damp, which in some cases would result in sanitary floor slabs. It also prescribed the waterproofing of walls and floors, but, in the projects consulted in this first period where the structural system mainly used is load-bearing walls, apart from the brevity of the project documentation, there are no project prescriptions in this sense for dwellings located on the ground floor, which was the most common situation in this first period.

The second mandatory regulation for the dwellings under study was the Order of 12 July 1955 approving the text of the technical ordinances and construction standards for “low-income housing”. In these regulations, just as the prescriptions for dwellings in the first group are limited to the fact that the building must comply with existing municipal ordinances, for those in the second group, to which all the dwellings under study belong, the following are established: minimum project contents, details of the urbanisation projects in accordance with existing planning, suitability of the land and its valuation (Martínez-Corral & Cuéllar, 2020).

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Continuing with the use of ceramics in the construction of railway housing, regarding the floor slabs, in the first period analysed, corresponding to the construction of housing by RENFE, the so-called “autarkic” floor slabs prevailed, imposed by the restriction on the use of iron in construction (Decree 11 March 1941 (BOE no. 71 of 12 March 1941) in force until the publication of the Decree of derogation of 19 January 1956 and, subsequently, the approval of the MV 101/1962 standard, on “Actions in construction”. It should be pointed out that, despite the repealing decree, another subsequent decree was issued (Decree of 26 July 1957) which warned against the excessive use of metallic materials and that it would be advisable to issue a provision regulating their use, given the scarcity of the material. The policies of the time, in addition to the restrictions imposed, stressed the need to use traditional techniques. Along these lines, the General Directorate of Architecture called in its bulletin in 1947 for the use of traditional materials and techniques. Given the precariousness of materials and labour, the possibility of a certain guarantee and quality, albeit minimal, was seen in ceramic materials. The information bulletins of the Directorate General of Architecture (BIDGA) were published quarterly from December 1946 to the first quarter of 1957 (Pérez Escolano, 2013) and served as a chronicle of the architectural practice of the time. Essentially, these are slabs that were made with ceramic lightening elements and in situ or ceramic ribs with little reinforcement on the tensile side (one or two steel bars). The top slab, then called the “compression layer”, was 4 or 5 cm thick and had no reinforcement. There was also a variant of these slabs without an upper compression layer, which could be assembled on site or in the workshop (Muzquiz de Miguel, 1945). From the 1960s onwards, once the period of restriction had been overcome and, in our case, coincided with the dwellings built by the railway cooperatives, the type of slab that became the norm was made up of prestressed concrete joists. Between one period and another, around the 1950s and 1960s, the use of calcium aluminate cement (aluminous cement) became popular, especially in joists, which was banned for this use from 1979 onwards. To date, we have not detected its use in any of the projects analysed. In the cases under study from this first period, slab edges of between 13 and 20 cm are observed. Although the most commonly used solution is the 15 cm edge. They are made up of hollow bricks arranged every 25 cm (length), leaving a space of 5 cm for the ribs reinforced with a 12-14 mm steel bar on the lower face. The grooving of the brick walls was a guarantee of adhesion with the mortar. The most repeated dosage of mortar used was 1:2:3, using 340 kg of cement per cubic metre, and the coatings did not reach a centimetre, which is one of the most common causes of pathology detected in these slabs due to the lack of protection of the reinforcement. The regulatory requirements of the period meant that, in projects prior to 1957, any type of prefabricated slab was explicitly disdained because it was considered that “they were only weakly reinforced for rigidity before being placed in their definitive position, the reinforcement being completed afterwards with the small ribs that join them together. This, which is theoretically perfect, has the risks of prefabrication imperfections and failures due to deformations when the joists are raised to the floors”.  However, the reality is that the limitations imposed on the use of iron during the post-war period led to the lowest quality moment in the construction of floor slabs (Azpilicueta Astarloa, 2004).

Illustration 1. Self-supporting slab section of the RENFE housing group in Las Matas (Madrid). AMF, project M-5476-VP. 

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After the Decree of 11 March 1941, which limited the use of steel, until the approval of the MV-101/1962 standard on “Actions in Building”, which repealed the previous limitations, the use of iron in building was restricted, giving rise to the corresponding regulation detailing the prescriptions in this respect during the design and execution of the work. (BOE nº 214, 2-8-1941). These regulations were based on prescribing technical solutions that would help to save iron, explicitly prohibiting its use in construction elements that could be built with other materials. In the rest of the constructive elements, the project design was urged to make the greatest savings in iron.

This affected the structural typologies, leaving aside the evolution made in previous years in the use of metal structures, frequently employed until 1936 (Lahuerta, 1965), as well as the construction of high-rise buildings. Therefore, with regard to vertical structural systems, during the entire period of the restriction, practically coinciding with the predominance of RENFE as a developer of housing for its employees, the ceramic brick load-bearing wall, without any quality control of the manufacturing process, was the structural system almost exclusively used as part of the misnamed “traditional construction” (Azpilicueta & Araujo, 2012).

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