The palace was designed by Baldassarre Longhena at the behest of the Bon family, who could not complete the building because of lack of liquidity and ceded it to the rich Rezzonico family, who entrusted the works to the architect Giorgio Massari.
The imposing Istrian stone facade on the Grand Canal in Venice, completed in 1756, is on three levels, of which the ground floor is ashlar and the two noble floors are framed by twin columns, with arched windows and sculptures on the vaults.
Before the restoration, the façade was in an advanced state of deterioration with many detached elements and thick black crumbs that prevented the reading of the sculptural apparatus.
Conservative restoration operations were aimed at stopping the alteration processes through a first material and structural consolidation with control of all the elements in danger of falling and static checks of the balustrades, at the same time biocidal treatments were applied for the deactivation of biological patinas and the drying of the upper plants.
The cleaning operations were carried out gradually and differentiated according to the state of preservation of the treated surfaces and the type of deposits to be removed, the control of the cleaning degree and the use of laser instruments for finishing allowed, moreover, the maintenance of the original oxalate patinas present only in the areas not washed.
Subsequently, the altered grouting was replenished by applying lime-based mortars and micro-stuccing micro-spraying areas in order to facilitate the drainage of rainwater and prevent future alterations caused by frost and thawing cycles.
The preservation works, particularly complex due to the different quality of the Istrian stone used by Longhena and Massari, have made it possible to secure the rich decorative apparatus and rediscover the original surfaces and patinas still present on the façade.