The present invention provides a coating composition, a method of coating a substrate, and a coated substrate, (e.g., a coated cemented fiberboard article). In preferred embodiments the coating composition includes one or more latex polymers and an aliphatic epoxy resin system. The coating composition can include one or more coating compositions that may be applied in one or more layers. A coated article comprising a cement fiberboard substrate and a coating system applied to the substrate is also provided. The article includes a first coating system applied to the substrate, wherein the first coating system includes an aliphatic epoxy resin system having an aqueous dispersion of polymer particles, optionally a silicate additive, and optionally one or more olefinic compounds and initiator for same. The first coating system preferably includes one or more coating compositions that may be applied in one or more layers. In a preferred embodiment, the first coating system is applied to all the surfaces of the substrate (e.g., the front side, back side and edges of a board). The coated substrate may then be coated with other optional coatings, e.g., decorative or protective topcoats.