The rehabilitation of buildings: an interdisciplinary approach
Rehabilitation is increasingly becoming a topic of reflection and consideration, mostly due to factors like the attractiveness of historical centresfor tourism, the social importance of architectonic references in the communities, and the rising taste for the charm and complexity of historical buildings, both in the scope of housing as in commerce and services. Consequently, the drive for the preservation of an historical identity with architectonic value is, more and more, present in the urban and architecture planning. Likewise, we can also observe an increasing concern with the materials preservation and with the structure reinforcement of buildings with historical significance, emerging in the area of engineering several solutions that progressively answer to the problem of material and immaterial preservation.
Assuming the intention to rehabilitate or to renovate a given building, one must ask the following questions: What are the options or what are the limits to a rehabilitation intervention? What is, after all, the rehabilitation of buildings?
Rehabilitation is “the concrete possibility to reuse the architectures, the structure and the construction elements of old buildings, adapting them to the needs and demands of contemporary use, but avoiding the loss of its essential aesthetical, historical, architectonic and urbanistic values” . This concept was implemented in the Declaration of Amsterdam in 1975, where, for the first time, the rehabilitation of historical areas is mentioned in opposition to the restoration on merely a few selected buildings, accentuating the importance of the participation of the population in this process. This concept is different to the concepts of Restoration and of Conservation, since it incorporates the adaptation to the needs and demands of contemporary use. Some of the new functions may nevertheless implicate the over-adaptation of the buildings, and consequently the destruction of a large part of the historical materials, of the spatial distribution or of the “marks of time”. For that reason, rehabilitation entails a balanced choice and a definition of the limited number of functions that a building or a part of a building can maintain without destroying his own values.
The values of a building are what characterises and qualifies it. Based on Riegl’s texts, we can group tem in the following categories: historical values, deliberate commemorative values, age values, use values and art values. These categories integrate different characteristics of the building, both material features, as historical construction techniques or materials that have a value linked to its age (for example a stucco worked ceiling or a mosaic pavement), as well as formal or stylistic characteristic (for example a room with a particular design or a building that fits a renowned architectonical movement, and also more subjective characteristics that are linked with meanings that are associated with the building due to, for example, a specific event that may have occurred there.
Some of these values are directly related to the temporal and stylistic context of a building and to the study of its evolutions. These factors lead to a more informed and holistic contemporary rehabilitation intervention. The historical contextualization of the building contributes to the renovation of its identity perception, rehabilitating it not only physically but also in its identity.
The preservation of the building’s identity is directly and strongly linked to the authenticity maintenance of its characteristics. Thus, the discussion on authenticity became currently a fundamental topic and was inclusively the object of a transnational meeting that resulted in a new reference “letter”: The Nara Document on Authenticity. According to this document authenticity is “the essential qualifying factor concerning values”, considering that “our ability to understand these values depends, in part, on the degree to which information sources about these values may be understood as credible or truthful” .
Considering all these aspects the next step will be an evaluation of the building we are working on. This evaluation or diagnosis is made in different perspectives. First the authenticity point of view, establishing a hierarchy of the different levels of valuation. By defining these different levels, it is possible to then adapt the type and depth of the intervention to each level, for example: strict restoration and conservation, cautious rehabilitation, rehabilitation with integration of new construction, reinterpretation of the existing volumes by adding new construction, or partial or total demolition. Depending on the situations, for each case there will be a larger or smaller number of levels.
Apart from the authenticity diagnosis, there is also the need for a structure and material diagnosis of the building: “Information is essential on the structure in its original and earlier states, on the techniques that were used in the construction, on the alterations and their effects, on the phenomena that have occurred, and, finally, on its present state” . This stage of the studied object’s analysis does not end in the knowledge of the current material and construction components, but broadens to the knowledge of history, the building’s modifications, the techniques and materials used in the construction, and of its architectonic characteristics.
In this evaluation of the construction and structural behaviour it is important to have an holistic vision of the studied building, since it is vital that the intervention considers the building’s integrity, instead of a lone intervention that is disconnected from the global behaviour of the structure.
Following the same idea, every evaluation or intervention in an historical building must be oriented by this same holistic approach, considering its several elements and different possible strands in the analysis.
The subjects we mentioned are just a few of the fields of study that can be involved in a rehabilitation process. The main subjects to consider will be history, architecture, restoration, archaeology, engineering, but there are many other subjects that can be crucial to the completion of a cohesive rehabilitation project, like, for example: economics, developing analysis to the feasibility of the intervention considering all the previous aspects; law and regulations studies and, many times, contestation as not always the construction regulations are adapted to existing buildings, too often being highly demanding and putting at risk the integrity of the historical buildings; sociology, considering the impacts of a renovation or studying the significations of the building to its community; among others.
“Specialization is the way civilization moves forward – and perhaps it is the way it will destroy itself. Faced with a complex entity we split it up, catalogue the parts, study and develop them separately and then fail to put them together again.” Ove Arup
Often architects fear that their field of intervention can be diminished by other disciplines that would pose “problems” or “barriers” to the extent of the architects’ intervention. Throughout my study of rehabilitation, it has become progressively clearer how important it is, in the stages of analysis and diagnosis, to obtain the most possible knowledge about the building where the intervention will occur. This knowledge, only possible if obtained from all the areas mentioned before, is important to guarantee a respectful intervention but also vital to avoid further modifications to the project when the intervention has already started. Instead of reducing the intervention capacity of the architect, this multi-disciplinary knowledge of the building becomes the fulcrum of the project, providing clues, ideas and solutions.
One can conclude that all the aspects previously mentioned deeply influence the conception of the architecture and rehabilitation project, and that they should continue to integrate the post-project development of the building throughout time. In any intervention of this nature, it becomes essential to have a multi-disciplinary team that works together, in order to guarantee that all aspects are developed by the skilled specialties, in great tune and with shared goals.
Text by Inês Cabrita, 2015
Faculdade de Arquitectura da Universidade de Lisboa
 Translation from Guia Técnico de Reabilitação Habitacional coordination by J. V. Paiva, J. Aguiar e A. Pinho
 The Modern Cult of Monuments: Its essence and its development, Alois Riegl
 Translation of the characteristics named by João Mascarenhas Mateus in pages 281 to 282 of Técnicas tradicionais de construção de alvenarias: a literatura técnica de 1750 a 1900 e o seu contributo para a conservação de edifícios históricos, 2002.
 The Nara Document On Authenticity, Nara (Japan) 1994
 ICOMOS Charter -Principles for the Analysis, Conservation and Structural Restoration of Architectural Heritage (2003) ratified by ICOMOS 14ª General Assembly in Victoria Falls, Zimbabué, 2003.
 in TAYLOR, Becci, “Why don’t we design better?” in The Huffington Post.