The protection of reinforced concrete architectural heritage

The protection of reinforced concrete architectural heritage

Ugo Carughi (ICOMOS Italia)

We can consider reinforced concrete technology as the most recurrent in 20th century construction, both in works of structural or social commitment and in ordinary buildings of a prevalently residential nature. The latter, thanks to the standardization of the construction phases, have led to the rapid urbanization of vast territories, contributing to increase in some areas the phenomenon of unauthorised development.
The preservation of works belonging to the heritage of the twentieth century is based on the preliminary recognition of their cultural interest and the consequent law decrees of protection issued by the single nations. However, for more recent works in many countries there is a 'programmed delay' in the listing procedures, which inevitably compromises the possibility of conservation. This delay, which mainly affects works dating from the second half of the 20th century, may favour irreversible modifications or even destruction. For those built of reinforced concrete, there is also the risk deriving from the natural deterioration of the structural parts, often aggravated by the lack of adequate maintenance.
Paradoxically, the delay in the listing decrees is contemplated by the very same regulations of protection in many countries, fixing a period of time between the construction of the work and the eventual declaration of cultural interest, in order to guarantee a sufficient historical perspective. This inevitably affects reinforced concrete works.

Of the more than fifty countries on the European continent, only twenty adopt this criterion. Among these, more than ten expressly provide for its derogation. The situations vary from one country to another with different modalities and timeframes depending on the respective historical events and contextual circumstances. In the republics of the former Soviet Union, for example, the damnatio memoriae to which certain periods are subject conditions the judgement of entire categories of works. In Germany, where there is no time limit in any of the sixteen states of the Federal Republic, the protection of buildings from the communist period has become more difficult since the fall of the Berlin Wall.
Among the countries that gravitated in the ex-Soviet Union from the end of the Second World War to the early '90s, Bosnia and Herzegovina has set the date-limit of 1960, however derogable; in Hungary the undeclared term of 50 years from the realization of the work is only indicative; in Ukraine an unofficial threshold of 40 years is tacitly applied; in Russia the limit of 40 years can be derogated to protect particular works, even a few years after their realization. We also find such a deterrent in areas with a different culture, such as the Netherlands, where specific indications can disregard the last useful date (1965). In Scotland, it is possible to protect works threatened by demolition or tampering, even if they were built less than 30 years ago, the threshold in force throughout the United Kingdom. Finally, in Italy, the threshold of 70 years does not prevent a building from being protected regardless of its specific qualities, but only because of its close link with national history or culture.

Even if most European countries, including some with strong historical traditions such as France and Spain, do not contemplate any time limit, the protection of the twentieth century is often neglected. The action of European Union bodies tends to build a homogeneous orientation with the formulation of Charters and Conventions on heritage which, however, remain excluded from national regulations.

The consequent effects of the lack of timeliness in protecting the most recent heritage, of which reinforced concrete architectures and structures form the main part, has contributed to the lack of consideration concerning the value of certain works, thanks also to the omnipresent recurrence of this construction technology. This circumstance means that even reinforced concrete works that could rightly be part of the heritage of the 20th century are subject to the obligation to follow compliance standards: seismic adjustment, elimination of architectural barriers, fire safety, reduction of energy consumption, accessibility, capacity, safety of users and maintenance staff, etc.. Or, in the impossibility of complying with continuously updated standards, they are abandoned to unstoppable deterioration or condemned to demolition.
Yet, the recognition of cultural interest could allow derogation from the rules on safety and management, with an approach aimed at achieving the same result without having to comply with predetermined procedures.

Some examples: In Finland, if a building is listed, energy saving can be achieved by complying with the regulations in force at the time of its construction. Thus, in Alvar Aalto's house in Helsinki (1935-1936) only partial improvements were made by inserting as many layers of insulation in the air space of the external walls as could be contained. In Le Corbusier's Maison La Roque in Paris (1923-1925), after restoration work (2008-2009), the number of visitors was limited to 20, thus implementing a preventive management measure, without invasive intervention to adapt the building to new standards. In the Couvent de La Tourette in Eveux, designed by Le Corbusier himself (1953-1960), a highly sensitive smoke detection system was installed, which avoided the installation of fire doors that would have broken up the original continuity of the corridors. In Albert Zeyer's school complex in Dula, Lucerne (1930-1933), to enable energy savings in the early 2000s it was verified that the replacement of the thin external window frames would have given partial results, compromising the aesthetics of the building. Instead, the ground floor and roof horizons were insulated, only the glazing was replaced, and the heating system was upgraded.
These examples show how the protection of a work does not mean absolute immutability. In the words of Leonardo Benevolo, the need to conserve ... does not at all mean renouncing to intervene, or pretending to leave things as they are, blocking any initiative. Works of architecture, left to themselves, do not stay still at all, and to conserve them it is necessary to intervene in a certain way, and therefore modify reality. (L. Benevolo, speech at the I.N.U. debate, La difesa del paesaggio urbano e rurale, in "L'architettura, cronache e storia, n.21, July 1957).