Porta della Carta, stonework conservation of the entrance to the Ducal Palace

Bust of St Mark halfway through cleaning in 1976
Porta della Carta, Giovanni and Bartolomeo Bon, 1438
Cherub climbing a crocket: flamboyant Venetian Gothic stonecarving

About the project

The contract for this gateway, the principal and ceremonial entrance to the Palazzo Ducale, was signed in 1438 by the architect-sculptors Giovanni and Bartolomeo Bon. The polychrome stone decoration is one of the last and most flamboyant examples of the Venetian Gothic style.

Scaffolding on three floors was erected with an elaborate wooden structure encasing the full height of the gate. Electricity, hot and cold water were laid on and there were windows on each floor and a trapdoor and winch to haul up the delicate and and specialised equipment being used.

Thanks to what had been learnt during earlier work on the Loggetta on the other side of the Piazzetta, efforts were made to restore the damaged stone in situ.

The surface deterioration due to sulphation, algae and other causes was considerable. The black incrustations were softened using bio-pack poultices , which, when removed revealed traces of colour and gilding on the Bon sculptures. More delicate residual cleaning was done with a new aero-abrasive device and the statues were reinforced and protected against further erosion by impregnation with a silicon resin, using a vacuum process specially adapted for external surfaces. Finally, a reversible protective skin of resin and wax was applied.

The cost slightly exceeded the sum offered, even though scaffolding and services were supplied by the Palazzo Ducale administration, but the Headley Trust generously agreed to top up its funding.

Project location

In brief

  • This early project undertaken between 1976 and 1979, was selected after the Headley Trust offered a substantial sum for a repair project. 
  • Stonework conservation was a particular focus of Venice in Peril’s work especially in the years after 1966, partly because of the very obvious damage that years of pollution had caused and partly as a result of the support of the V&A Museum in London, which loaned its conservator Ken Hempel.
  • The work on the Porta della Carta and the Loggetta was carried out as a collaboration between British and Italian conservators, with the help of conservation students in the summer months.
  • The image of St Mark partway through cleaning and the four lower thumbnails on the right, are scanned from photographic prints dating from 1976-79. One of them shows the elaborate covered scaffold tower that was erected during the project.

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