• Some damaged monuments need to be restored while others simply need to be preserved, according to our partner The Conversation.

  • In either case, it is essential to rethink the interactions between old and new materials.

  • The analysis of this phenomenon was carried out by Bruno Phalip, professor of Art History and Medieval Archeology at Clermont Auvergne University (UCA).

As much as the word conservation is unknown, the word restoration is seen as positive evidence for the monument.

Classifications as World Heritage by Unesco, Historical Monuments in France, or their equivalents in Europe (English Heritage Buildings, Baudenkmal, Monumenti nazionali italiani, Patrimonio Cultural de España, classified properties of Belgium / Kulturdenkmal or Beschermd erfgoed ... ), show how much “protection” is integrated by audiences, such as institutions in each country.

Likewise, in the face of the urgent need for safety, the measures taken are for the most part accepted, despite impatience.

Whether it is the scaffolded choir of the cathedral of Tournai in Belgium or the upper parts of Notre-Dame de Paris, the functioning of the institutions is not called into question.

Debates and institutions

After lively debates, despite sometimes contradictory wishes, the answers given are hardly criticized beyond specialist circles.

The heritage institutions of the Ministry of Culture, the National Heritage and Architecture Commission, Historical Monuments, the Historical Monuments Research Laboratory and the Regional Directorates of Cultural Affairs, respond appropriately, by providing solutions that tend to respect for laws (1887, 1909, 1913 and subsequent modifications), appropriate regulations (landscapes, sites, monuments, places of worship, furniture, archeology, etc.), such as protocols (funding, resources, methods, ethics, etc.).

In Tournai (Belgium), the scaffolding mesh playing with the stained-glass windows © B. Phalip / The Conversation

These choices prevail for Notre-Dame despite an interventionist party calling for the acceptance of an “architectural signature” (glass roof, steel spire, contemporary materials and innovative shapes, etc.) presented as a guarantee of modernity. to take the decision.

The spire built at Notre-Dame by Viollet-le-Duc in the 19th century, before the Republican laws on historic monuments, has become a work in its own right.

However, a cathedral is not a museum (Ming Pei pyramid in the Louvre Museum);

reason also prevailed.

The protection and the rules of the restoration thus prevailed in the respect of the institutions and laws.

However, if the necessity and the modernity of the restoration measures (advanced techniques, materials and engineering, digital tools, analyzes, scientists' research time associated with the short construction time, etc.) are obvious at Notre-Dame, they do not do not obscure the conservation needs of thousands of other monuments.

Protective nets at Notre-Dame de Paris © B. Phalip / The Conversation

These do not benefit from the emotion, the means or the projects, now associated with April 15, 2019. The recent fire in the church of Romilly-la-Puthenaye (Eure) shows the limits of media coverage, patronage (Versailles gates) such as interest in buildings as important to human communities as the largest of them.

When "reconstruction" supplants "restoration"

In doing so, in everyday language, for Notre-Dame, as for the church of Romilly-la-Puthenaye, the word restoration is hardly used any more, in favor of reconstruction, which betrays a weakening of the primary meaning.

Restoration - despite perceived limits in Chartres or at the palace of the Dukes of Brittany in Nantes - involves debated rules, reconstruction can be freed from them, including for protected buildings.

We have to be careful about it.

The reconstruction of the north tower of the abbey of Saint-Denis, the reconstruction projects of the Tuileries or the castle of Saint-Cloud bear witness to this semantic shift and are inhabited by the same frenzies aimed at correcting history with the sole future a past erected as a myth (Berlin Palace, Berliner Schloss des Hohenzollern).

Forêt-Fouesnant (Finistère);

pinnacle and statue after treatment with biocide (lichen) and cleaning;

surfaces are altered © B. Phalip / The Conversation

Before restoring, patient maintenance, respectful of the signs of aging that affect the monument, must be privileged with a view to its conservation.

Transformed, but in good condition or ruined, the sites may be the subject of development, consolidation or interventions framed by the recommendations of international conservation charters: Athens in 1931, Venice in 1964, Nara in 1994 or Krakow in 2000. The actors of the restoration refer to it with the declared will to respect the recommendations (La Chaise-Dieu, Chartres).

However, in France, as in Europe, voluntarism reigns, accompanied by strong interventions at the cathedral of Puy-en-Velay, Notre-Dame-du-Port in Clermont-Ferrand, Sainte-Gertrude de Nivelles in Belgium or the Saint cathedral. -Georges de Limburg an der Lahn in Germany.

Beautiful examples exist, the object of jealous attention, such as the cathedral of Tournai in Belgium, well documented and pampered for more than twenty years, Notre-Dame de Paris for two years now, or Angkor Wat in Cambodia for three decades.

Restoring is probably not always preserving

It must be admitted, however, a century and a half of restorations does not preserve the monuments.

The unsuitable use of materials and products contributes to the acceleration of weathering processes, by combining poorly with stones, two millennia old for an ancient monument or sometimes a millennium for the Middle Ages: cryogenics by micro- abrasion, hydrogumming with abrasive powder, alumina or fine glass powders.

Our “Historical monuments” file

The interaction between old and new materials is - most of the time - harmful, not taking into account the balance that is established between the centuries-old monument, its environment (climate, landscape, fauna and flora) and current sites in industrial techniques (grinders, pneumatic hammers, drills, etc.).

The use of dense or waterproof materials (cements, water-repellent products, etc.) no longer allows a balanced “breathing” of the wall over the long term (lime mortar, ventilated masonry, etc.), but also repeated abrasive cleaning, polluting treatments (sites, subsoil water) by biocides (biofilm, plants), or soils made watertight (bitumens, etc.) are harmful.

Biodiversity is considered to be an alteration factor for the monument;

it is not only cyanobacteria, lichens and mosses that have populated the facings since the time of construction.

Insects and rodents, birds themselves are considered pests, about which solutions are used: nets visible in Germany in Nuremberg or even in England in Exeter.

Tichodrome ladder of an archaeological site;

birds are also considered to be pests (beak and talons, droppings) © B. Phalip / The Conversation

Several problems arise in addition to the aesthetic question;

these damaged and poorly fixed nets involve friction due to the action of the wind;

they are also the electro-repellent systems attached to the sculptures and architectures (Auxerre cathedral) with metal fixings and glues added to the anti-pigeon spikes.

The marks of aging and biodiversity are thus banned in favor of whitewashed monuments, in environments adapted to the economy of tourism, which contravene prudent protocols recommending discreet interventions.

The monument's greatest adversary is not time, but the human action of our time.

Modernity thus shows its limits, in the absence of measure, prudence and allocation of research with a view to respecting the biosphere intimately linked to the monument for centuries.

Lichen and moss biofilm;

all are associated with the alteration of the stone of the monuments © B. Phalip / The Conversation

The future ?

No longer use biocides, consolidating or water-repellent products;

avoid systematic cleaning.

From this point of view, biological mortars and bio-mineralization constitute encouraging indices (bio-cullet from Argenton-Château and Thouars; LRMH), as well as the soft caping (plant cover) recommended by the teams of English Heritage and widespread in Britain.

The immediacy of bad solutions should be avoided by seeking other means than those usually recommended which lead to excessive mineralization of the monument, the surfaces of which are altered by abrasion and made uniform.


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This analysis was written by Bruno Phalip, professor of Art History and Medieval Archeology at Clermont Auvergne University (UCA).

The original article was published on The Conversation website.

Declaration of interests

Bruno Phalip does not work, does not advise, does not own shares, does not receive funds from an organization that could benefit from this article, and has not declared any affiliation other than his research organization.

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