A shutter assembly having at least one rigid edge and at least one hanger edge is described. The rigid edge provides stability to the shutter assembly and the hanger edge allows the shutter assembly to be mounted to a dwelling. The shutter assembly can be formed in an open mold from a cementitious slurry comprising gypsum cement and water. A reinforcing mat or fiber can be disposed in the mold and saturated with the cementitious slurry. A tool disposed adjacent the mold and including a plurality of rotatable sections can be used to form the rigid edge and the hanger edge.