Abstract: A synthetic fire resistant and flame retardant shake shingle suitable for roofing construction is formed of a water-extended polyester resin that has been molded to the shape of a shake shingle and dried to form a semi-rigid, cellular lightweight structure containing a filler of fiberglass pieces substantially uniformly dispersed throughout the cross section of the molded and dried polyester resinous structure. In one embodiment, the ratio of polyester resin to fiberglass pieces to water in the molding formulation is about 3 to about 2 to about 5.5. In an alternative form of the invention, the fiberglass pieces are replaced with a coarse fiberglass mat impregnated with the polyester material to form a core of the resulting shake shingle.