Despite the widespread use of ethyl silicate for stone consolidation, the investigation of its reactivity with the different supports is still in progress. In this paper, the pozzolanic behaviour of ethyl silicate is investigated, by means of experimental mixtures of commercial ethyl silicate and slaked lime, and the occurrence of C–S–H formation is shown. The ability of ethyl silicate to penetrate in porous building materials as a liquid solution and, only after curing, to give rise to a pozzolanic material encourages the application of ethyl silicate for the consolidation and protection of reinforced concrete, as well as for the consolidation of modern cement-based mortars having artistic value (Art Nouveau cement-based mortars, etc.). The pozzolanic effect of ethyl silicate can be exploited also for the formulation of new consolidating materials (e.g. with nanolime).