After the precautionary phases of pre-cleaning and pre-consolidation of the stone layer which was in the process of detaching, the surface was cleaned by applying a specific reagent.

A special compress was applied in the cupola and on the capitals so as to remove the black crust of deposits. The stone was then consolidated with ethyl silicate and the application of specific mortars. The non-salvageable blocks at the tip of the lantern were substituted.

The micro-fissures have been plastered with an elastic, highly absorbent mixture so as to counteract seepage. The surface of the stone was then treated with a product that will decrease water absorption.