In the last decades the conservation and protection of historical buildings, after the increased atmospheric pollution, became a priority in all industrial countries. The natural stones exposed to a dramatically increased aggressive environment show their durability limits. The necessity to study new protective systems specifically projected to defend the materials according to the peculiar characteristics of each stone substrate. The complex heterogeneity of stone substrates demands an adaptable and efficient shielding strategy in order to satisfy the defferent protection requirements such as water repellency, permeability, photochemical and thermal stability and transparency. These characteristics, obviously, have to be maintained as long as possible. Such modulated multi-response behaviors can only e attempted with materials based on multifunctional copolymers. Different polymeric materials have been employed as coatings for building materials but these products were always transferred from industrial applications tot the conservation of Cultural Heritage without a deep knowledge of their properties and without a real optimization of structures for stone protection. Since 1977 in the framework of the C.N.R. Target Project “Safeguard of Cultural Heritage,” there is a specific research to synthesize and to investigate the performance of new fluorinated acrylic copolymers expressly tailored as protective for building materials [1]. In this paper the protective performances of two new fluorinated acrylic copolymers 1H, 1H, 2H, 2H-perfluorodecyl metharcylate/1, 1, 1, 3, 3, 3-hexafluoroisopropyl methacrylate/ethyl methacrylate/methyl acrylate (XFDM/HFIM/EM/MA) and 1, 1, 1, 3, 3, 3-hexafluoroisopropyl methacrylate/ethyl methacrylate/methyl acrylate (HFIM/EM/MA) are evaluated and compared with Paraloid B72, a commercial copolymer ethyl methacrylate.methyl acrylate (EM/MA) and its partially fluorinated homologous 2, 2, 2-trifluoroethyl methacrylate/methyl acrylate (TFEM/MA). These four copolymers have been tested on two different stone materials: Candoglia marble, a very low open porosity stone (<2%), and Noto calcarenite with an high open porosity (about 30%); both materials largely employed in the historical Italian architecture. The copolymers were applied and tested on a series of stone specimens according to the UNI-Normal protocol [2] before and after accelerated photo-aging. Moreover the data are compared and explained with a dynamic contact angle study, carried out on the polymeric films, to evaluate the hydrophobic properties of the coated surfaces. This papers aim at investigating the protection efficacy of the different polymers and elucidating the importance of a dynamic contact angle analysis as an instrument for clearer comprehension of polymer surface distribution and protection effectiveness.