Restoration interventions in the classical buildings of the Acropolis started in the 1970s intending mainly to the protection and preservation of the monuments. The failures of previous restorations had caused extensive damages and fractures and cracks in the marbles; moreover, air pollution necessitated the removal of the sculptures from the monuments and their safekeeping in a protected environment. Since then, new unexpected problems of stability have surfaced, triggered by other reasons, such as fires, explosions and earthquakes. Interventions brought about an enhancement of the monuments through supplementary restorations and relocations of architectural members that had been positioned in the wrong place. The purely rescuing character of the initial programme evolved and encompassed anastelosis programmes that not only improved the static efficiency of the monuments but also their readability. Until today the programmes completed are the restoration of the Erechtheion, the Propylaia and the temple of Athena Nike, while the works of restoring the Parthenon and the Acropolis Wall are still in progress.
The main structural interventions in the Acropolis monuments follow the next order:
Dismantling parts of the monuments, removing the sculptures and replacing them with cast copies, restoring the marble architectural members while paying special attention to the conservation of authentic material, reassembling, and also correcting the restoration mistakes of previous restorations. The restored parts of the buildings are dismantled in order to handle problems of stability. Then, after the conservation and restoration of individual architectural members is completed on the ground by removing the remains of older interventions (oxidized iron, decayed and corroded concrete, various adhesive materials and cement mortars), the fragmented members are joined back with reinforced titanium and special cement mortar. In case a new filling is needed, Pentelic marble is used. The restored members are placed on the monument in their initial position with the use of new titanium clamps and after the previous restoration mistakes are corrected.
ESMA’s established principle has long been restricting interventions in the areas of the monuments that have either been damaged by previous interventions or are in a dilapidated state. However, as oxidised clamps are found in areas that cannot be easily seen, the problem can only be tackled through dismantling not only parts of the monuments but also their architectural members and replacing the clamps with new titanium ones. The key criterion for the structural restoration of the marbles is to respect the original material. A longstanding effort of the Service has focused on the reversibility of the interventions, that is the possibility to restore the monument to the state it was before the interventions so as it can conserve all information it contains and allow future interventions to correct mistakes made during the present interventions.