The physicochemical properties of the surface of aerial mortar samples simulating real wall paintings were studied in this work before and after the application of three different acrylic copolymer coatings: EMA/MA 70/30 (Paraloid B-72(R)), nBMA/iBMA 50/50 (Primal AC33(R)) and EA/MMA 60/40 (Elvacite 2046(R)). The behavior of the investigated parameters demonstrated that the physicostructural properties of the porous material were strongly altered by the presence of the copolymers. There was a drastic change of the physicochemical behavior of the interface between the work of art and the environment. Water capillary rise coefficients, water vapor permeability coefficients, water contact angles, surface areas, and pore size distributions were determined. The main effects observed were both the strong decrease of the surface hydrophilicity, and the decrease of the transpiration of the water vapor through the mortar surface. These effects are not recommended for suitable wall paintings conservation since, to prevent degradation, the painting surface must have both high hydrophilicity, and high water transpiration. Scanning electron microscopy (SEM) indicated that the morphology of the porous matrix surface after the application of the copolymers strictly depended on the nature of the copolymer. The interest of these results for the conservation of mural paintings was stressed.