The first restoration works date back to the second half of the 800: the building was in a poor state of conservation and this led to several campaigns of consolidation, also accompanied by distributional changes and reforms of the perforated patterns.
It also intervened at the staircase: the cracked steps were affected by the implementation of grappa iron and damaged the central column was enclosed by a wall pillar.
Unfortunately, the interventions in the nineteenth-century were gradually canceled by the oxidation of the metal elements and the consequences induced by the static of a hardening masonry pillar, which embraced the middle column of the ladder. It can be also added the degradation of the stone material.
In 1979, the Minnesota Chapter of the Word Monuments Found financed the restoration of the Scala Contarini del Bovolo in the context of the International Campaign for the Safeguarding of Venice.
The restoration project, developed in 1980 by architect Mario Piana of the Superintendent of Environmental and Architectural Heritage, was entrusted to the Venetian Building of Engineer Todeschini for structural reinforcement, and the company Lithos for intervention on the stone.
This intervention was designed with the idea of restoring the monument to a condition close to the original one, by searching for methods and materials that behave the least possible tampering of historical material.
The idea is also to remove the causes of the static flow, such as the replacement of the iron clamps as stainless steel elements and the removal of the pillar masonry, finishing with the cleaning and restoration of stone parts.
This restoration won the prize Torta in 1992 for the quality and competence demonstrated in its implementation.
The last renovation of Palazzo Contarini by the Institute of Recovery and Education has provided a unique opportunity to return to the usability of the staircase security most beautiful in the world.
The drafting of the final project dates back to 2006 and the executive to 2009.
The project for Palazzo Contarini del Bovolo was based on studies and very advanced analysis.
In relation to the investigations carried out, it was possible to identify some internal partitions and ceilings made recently that deprive the spaces of their characters, complicating the paths and creating a disadvantage position in the perception of the space. The project involved the elimination of these elements in order to redefine the redistribution of routes and to find more consistency.
It was ensured a clear division of the entrances and the spaces between IRE, City of Venice and the area open to visitors, a distinction also determined by security issues.
The intervention consists mainly in a new staircase connecting all floors of the IRE, placed in the other side of the Palace; in order to do this, it has been studied a finishing touch that recalls the materials of the lagoon through the transparency and the colors of blown glass sheets supported by a metal structure which also contains the elevator shaft.
The construction of the new staircase meets functional requirements, it is characterized as new and distinctive element of the restoration and aims to evoke some materials and counterpoint between the Palace and the outdoor staircase. Also the distribution of the structure was the most conservative possible of the existing construction, identifying two main distribution plans.
The interventions of consolidation of the horizontal planes are summarized in conditions of deformability and the increase of some elements. Structural improvements resulting from combined actions such as the reduction of the light through the onboard network, the increase of rigidity with reinforcements with double plank and plank nails, and replacement with wood restorations. The horizontal planes such stiffened have been linked to the perimeter walls with metal chains isolated and profile system steel whose purpose was to distribute stress on the masonry. In case, it has found valuable elements, consolidation solutions have been abandoned in favor of conservation. The other interventions were more conservatives: the identification, preservation, and integration of historic finishes (especially some decorations dating back to the early stages of the building that they encounter while on the external elevation at the staircase), the security and consolidation of all stone elements.
The construction site was an important moment of knowledge of the Palace, whose future preservation can refer to material collected and processed; these insights have also addressed some design choices, related for example to highlight some past phases of the construction of the Palace.
Additionally, this last intervention has given back to the Scala Contarini its main function: it has constituted a chance to give utility to a unique work.