This article highlights the possibilities of obtaining plasticized gypsum with compositions based on phenol-formaldehydetriethoxysilane. We also studied the physical and mechanical properties of samples obtained with a gypsum mixture containing various concentrations of polymer compositions, such as water permeability, flexural and compressive strength, including a decrease in water permeability up to 50-60%, an increase in flexural strength up to 20-56% was determined, for compression up to 20-47%.