A coated component having a composite substrate and a coating system disposed thereon is provided. The coating system is substantially non-porous such that hydrocarbon fuel or other carbonaceous fluids are prevented from contacting and impregnating the polymer matrix composite material. The coating system can include an aluminum layer or a film layer comprising a polyethylene film or a polypropylene film. Also provided is a composite fan casing for a gas turbine engine having a polymer matrix composite substrate and a coating system disposed thereon. Methods for forming a containment assembly of a gas turbine engine are provided.