Since 2002 over a hundred public schools have been built in Catalonia using prefabricated systems. Most of them serve as examples of a well-constructed prefabricated architecture and they have drawn the author's interest.The author chose these schools as his thesis topic, and during his research the author has found 138 sample prefabricated schools. Half of these samples were built between 2002 and 2006, as a specific project by the Catalan Education Department. But the other half had been built between 1970 and 1983, together with hundreds of other schools that had been built all over Spain according to govern deals called "Pactos de la Moncloa".Mainly, this thesis studies kindergarten and elementary centers built almost entirely out of prefabricated pieces between the years 1970 and 2006. More concretely, the author limited his study to schools built in Catalonia, which permitted a more in-depth study of the sample buildings and their systems by means of the resources at hand. Moreover, the schools built from 2006 to 2008 were discarded because they didn't improve the sample, and this was the way to get an historical view of the centers selected.This investigation started with three hypotheses: the schools included in the sample are a kind of building well-suited to prefabrication, prefabricated technology will prove to be the only one capable of producing these schools within time frame and budgetary constraints, and this prefabricated architecture has had a positive but irregular evolution.These hypotheses have been corroborated in this project, which has been developed in three main parts. First, samples are catalogued; second, samples are analyzed, and finally, the author draws his conclusions.In the process to catalogue the educational centers selected, the author carried out field research. This research allowed the author to catalogue this documentation, what has been done into three types of files: a general study of the 138 schools; a detailed catalogue of the 12 construction systems used to build these centers; and an in-depth study of the most representative school built with each construction system.Following this catalogue, the author presents his analysis, which starts with a historical review of prefabricated Spanish schools, with emphasis on the details developed in Catalan schools. In continuation, the author analyzes the samples from the same three points of view used previously while cataloging the sample schools. This methodology has been successfully applied and is considered appropriate for use in other studies of prefabricated buildings.The third section of this thesis presents the conclusions based on the analyses undertaken; from these, the author draws some recommendations for the construction of prefabricated schools in the future. Both proposals presented are based on rationality and they avoid subjective approaches to the prefabricated world. Furthermore, the author considers that the majority of his recommendations and conclusions can be applied to constructing prefabricated schools throughout the country. This research project proves that prefabricated construction systems are well-suited for schools, and their evolution has been positive but irregular. As well, the author recommends a revision be undertaken on the currently available systems in order to maximize their outcome. This redesign should consider the previous experiences and adapt these systems according to future necessities, based on teamwork by all the professionals who have worked in constructing schools with prefabricated materials.Finally, this thesis shows the qualities of a new technology for today's architecture, one closer to the values of our society: security, temporality, environmental awareness.The current crisis in construction could be an ideal moment to reflect on the need to design and build employing a more up-to-date, innovative construction technology.

La fachada ventilada es aquel cerramiento caracterizado por resolver la estanquidad al agua por medio de una cámara drenante continua en todo su plano. Para la definición de dicha cámara se precisan dos hojas que la limiten: la exterior, normalmente de juntas abiertas, y la interior.En la fachada ventilada convencional conviven dos sistemas constructivos muy distintos. Así como la hoja exterior y sus mecanismos de fijación han experimentado un gran desarrollo en estos últimos años que los ha llevado a un alto nivel de tecnificación acompañada del montaje en seco confiado a especialistas; la hoja interior sigue, en general, atada a la tradición.Esta convivencia no supondría ningún problema si permitiera concebir la fachada como un conjunto. Las pocas garantías, principalmente de estabilidad y planeidad, que da la hoja interior no permiten confiar en ella como soporte. La hoja exterior se diseña de manera autónoma, fijándose únicamente a los cantos de los forjados en muchos casos e incorporando más o menos complejos mecanismos para regular la planimetría.La hoja exterior no confía para su diseño en las bondades que una hoja interior correctamente planteada podría aportar.Actualmente están proliferando algunos ejemplos de racionalización de la hoja interior, desde el tabique seco de montaje in situ hasta los paneles y las chapas, pero aún así son pocos los que consiguen una lectura conjunta del sistema de fachada.Este trabajo se centra en el desarrollo de un panel para la hoja interior de la fachada ventilada. El panel será prefabricado y deberá dar una respuesta rigurosa a las funciones y requerimientos exigidos.Se parte de la hipótesis de que el diseño del panel depende de las distintas posibilidades de agrupación de las funciones básicas de la hoja interior sobre este elemento. Estas funciones son las indispensables para dotar al espacio habitable del adecuado nivel de confort térmico, acústico y de estanqueidad al aire. Se suman la protección frente a la propagación del fuego y dar soporte al conjunto de la fachada frente a la acción del viento y al peso propio. Las funciones que no satisfaga el panel las deberán resolver capas añadidas al sistema de fachada.La función que define al panel es la portante frente acciones horizontales y peso propio. Es la función que siempre deberá satisfacer. Las posibilidades de agrupación del resto de funciones determinan los seis tipos funcionales que ordenan las propuestas de panel.Esta taxonomía funcional permite tener claramente definidos los requerimientos que satisface cada panel, facilitando el conocimiento del comportamiento global de la fachada que integran. Es la definición que falta en la forma empírica actual de construir la hoja interior de la fachada ventilada.La satisfacción de cada función está directamente relacionada con las propiedades físicas del material al que se le encomienda. Combinar funciones implica combinar propiedades físicas concretas. No todas se pueden dar, con los valores que requieren las condiciones de confort, en un único material.Las diversas morfologías que se pueden dar en un panel son la herramienta que permite llegar a conciliar propiedades físicas a priori inconciliables. Por medio del laminado, nervado, grecado, etc. es decir, la heterogenización del panel, se pueden modificar varias de sus características.Este análisis teórico deriva en la búsqueda del material, o la combinación de materiales, más adecuada para resolver las diversas morfologías asignadas a los distintos tipos funcionales. Surgen quince propuestas de panel.Todas ellas se basan en productos de mercado que, o bien ya tienen, o podrían llegar a tener, una aplicación como hoja interior de fachada ventilada.La valoración de las soluciones de panel se realiza en base al diseño de fachada ventilada que permiten realizar, es decir contemplando todos los elementos añadidos que se deban disponer para completar el sistema. Los criterios de valoración los establecen los vectores de evolución en el sector.Estos vectores son tanto socioeconómicos como metodológicos. Los primeros los dictan exigencias sociales y económicas externas al sector (crisis de responsabilidades, exigencia del cliente de que el producto se adecue a sus necesidades, optimización de los recursos disponibles); mientras que los segundos, dan respuesta a los primeros, a partir de los criterios de diseño y producción actuales. Los vectores de evolución inciden de forma distinta en los diversos escenarios.Se plantean dos escenarios: el innovador y el conservador. Si uno estimula a la industria planteando necesidades a las que ésta debe dar respuesta, el otro va a remolque de ella.La importancia de cada uno de los parámetros que se desprenden de los vectores de evolución es distinta en cada escenario. Por otra parte, no todos estos parámetros establecen criterios valorativos que permitan destacar una solución frente a las otras (para algunos de ellos se dan valores similares en las distintas soluciones de fachada que surgen de la aplicación de las propuestas de panel).A los criterios que se desprenden de los vectores de evolución se deben sumar los que derivan de la satisfacción de las funciones de servicio (no contempladas en la taxonomía), así como los parámetros relacionados con la viabilidad de cada solución.Analizadas las soluciones de fachada, y por lo tanto de panel, desde la óptica de los citados criterios, se distinguen tres grupos que se caracterizan por la mayor o menor multifuncionalidad y la optimización del diseño.Dentro de cada uno de estos grupos se destacan las propuestas morfológicas más adecuadas para la resolución del panel.En definitiva, las propuestas de panel más adecuadas para la hoja interior de la fachada ventilada son cinco, distribuidas entre los distintos tipos funcionales. Tienden a ser homogéneas y de geometría plana salvo para los dos tipos funcionales extremos: cuando la función térmica está incluida entre las que resuelve el panel; y en el caso en que éste no precisa un grueso continuo. Para el primero se recurre al sándwich mientras que para el segundo al nervado.ProspectivaComo ya se ha dicho, los escenarios son diversos y no evolucionan de la misma manera ni a la misma velocidad. En este sentido se entiende que las cinco soluciones de panel destacadas son óptimas en cuanto que dan respuesta a escenarios distintos.Paralelamente a ellas se están abriendo paso elementos capaces de dar respuesta a muchas funciones a partir de la adecuada combinación en un único componente complejo a medida de diversos materiales especializados. Este panel de fachada es siempre multifuncional ya que no se contempla añadir sucesivas capas en obra. Su diseño es optimizado y por lo tanto se basa en materiales especializados. / Ventilated façades are all those enclosures that resolve the issue of waterproofing by providing a continuous drainage cavity that underlies the entire skin of the building. By definition, these drainage cavities are encapsulated between two membranes: an outer skin, which typically exhibits open seams, and an inner skin.Two highly distinct building systems live side by side in conventional ventilated façades. Thus, even though outer membranes and the mechanisms used to attach them have evolved greatly in recent years and have reached a high level of technological sophistication when dry-assembled by specialists, inner membranes are still shackled to tradition. Therefore, the design process for the outer skin cannot gain from the benefits of having a properly planned inner skin.There has been a recent proliferation in examples of rationalized inner skins, which range from drywall assembled on site to panels and plates. Still, few of these have been conceived of as part of an all-encompassing façade system.This study focuses on the development of a panel for the inner skins of ventilated façades. Though this panel will be prefabricated, it is still intended to provide a rigorous response to the functionalities and requirements demanded of it.The hypothesis of this study is that panel design is conditioned by the different possible ways of grouping the basic inner skin functionalities; namely, whether they will be met by a specific element or delegated to a separate layer.The most basic functionalities are those that are indispensable to make a space habitable in terms of thermal comfort, acoustical insulation and being airtight. To these three functionalities we can also add fire retention and the capacity to bear wind load and self weight. Whichever functionalities are not satisfied by the panel must be resolved by layers added to the façade system.The functionality that defines a panel per se is that of load bearing capacity with respect to horizontal forces and self weight; this functionality cannot be left unsatisfied. The different possibilities for providing for the remaining functionalities or delegating them to layers outside the panel are what shape the six functional typologies under which we can group the panel proposals.Having a functional taxonomy allows one to clearly state which requirements each panel satisfies, which in turn facilitates the task of defining the overall behavior of the façades they are used to build. It is precisely this definition of a unitary behavior that is missing from the empirical construction techniques used at present in the inner skins of ventilated façades.Whether all the functionalities are satisfied is directly related to the physical properties of the materials they have been entrusted to. Combining functionalities implies combining concrete physical properties, though not every functionality can be met by a single material at the levels that are required to provide adequate comfort conditions.The diverse array of morphologies that can arise in panel design provide designers with a tool for marrying physical properties that in stand-alone materials would be irreconcilable. By using techniques such as lamination, ribbing and stamped patterns - in other words, the heterogenization of the panel - many panel characteristics can be modified.This theoretical analysis is derived from a search for the single material, or combination of materials, that best suits each of the diverse morphologies that are assigned to each of the functional typologies. As a result, we have divided these into fifteen panel proposals, all of which are based on products available on the market that either are or could come to be used in the inner skins of ventilated façades.The evaluation of these panel solutions is based on whatever ventilated façade designs they allow one to build; in other words, they are evaluated by taking into account all the added elements that one must include to complete the façade system. The criteria used to evaluate them are established by the vectors underlying the evolution of the sector.These vectors are both socioeconomic and methodological. While the former are driven by social and economic demands that are external to the sector (such as a crisis of responsibilities, clients' demands that products meet their needs, or the optimization of available resources), the latter arise in response to the former, based on whichever design and production criteria reign at present. Thus, the vectors underlying the evolution of the sector have a different effect on each individual scenario.Two scenarios have been proposed herein: an innovative scenario and a conservative one. While the first stimulates industry by imagining the necessities that must be provided with an answer, the second follows it in tow.The importance of each of the parameters that stem from the vectors driving evolution is distinct in each scenario.Likewise, not all these parameters establish criteria for evaluation that allow one to identify one solution as objectively better than the rest, as in some scenarios similar values are given by distinct façade solutions that apply the panel proposals.To the criteria that stem from the vectors underlying evolution, one must add the criteria of satisfying service functionalities (which are not encompassed in the taxonomy), in addition to parameters related to the viability of each solution.Once the façade - and panel - solutions have been analyzed from the perspective of the criteria mentioned herein, one can divide them into three groups that are characterized by a greater or lesser degree of multi-functionality and design optimization.Within each of these groups, the morphological proposal that best meets the panel requirements will come to light.In short, there are five panel proposals that best meet the requirements of the inner skins of ventilated façades; one corresponds to each of the different functional typologies. They tend to be homogeneous and flat in plane except for the two extreme functional typologies: when the thermal functionality is included amongst those met by the panel, and in the case of a panel that does not require a continuous thickness in section. The former makes use of a sandwich panel, while in the latter the panel is ribbed.Prospects for the FutureAs we have said, there is a diverse range of scenarios, none of which evolve in parallel fashion to one another, nor at the same rate. Along these lines, the five panel solutions highlighted herein are understood as optimal insofar as providing a response to distinct scenarios.In parallel fashion, other elements are arriving on the scene that are able to provide a response to many functionalities based on a suitable combination in one complex component based on a range of specialized materials. Such a façade panel will always be multifunctional, as there is no aim to add successive layers to it on site. Its design is optimized already, and is thus based on specialized materials.