The intervention consists in a complex restoration both for the size of the facade both for the present problems. The choice of the most effective and less invasive methodologies has been the result of an accurate preliminary study conducted on the facade also by means of diagnostic investigations with radar technique for the verification of any latent instability. The cleaning is made with innovative techniques (laser), in full respect of the stone support: any type of deposit has been removed without whiten the façade, maintaining the natural patina that the stone has acquired in the course of time.