novel coating compositions for architectural use are provided , which include a quaternary ammonium silicate having a silica content of 10 to 60 % by weight and a liquid epoxide resin , besides the conventional ingredients , such as pigments , fillers , aggregates and water , and which are particularly capable of producing films having excellent adherency to mortar or concrete surfaces . if a stabilized silica sol is added to the compositions , films produced therefrom have much improved resistance to water at low temperatures as well as freeze - thaw stability .