Abstract: A method is disclosed. The method includes forming a groove in at least one of opposing planar surfaces of a cellular thermoform plastic substrate. The groove is formed at an edge region of the substrate. A stiffener is positioned in the groove, and a fiber matt is laid on the at least one planar surface containing the groove. The stiffener and fiber matt are embedded in a thermoset resin. The thermoset resin is cured to form a fiber reinforced thermoset plastic reinforcement. The substrate is then cross-sectionally cut to form a profile. The profile can be further finished to form a beveled siding for buildings.

Abstract: A method is disclosed. The method includes forming a groove in at least one of opposing planar surfaces of a cellular thermoform plastic substrate. The groove is formed at an edge region of the substrate. A stiffener is positioned in the groove, and a fiber matt is laid on the at least one planar surface containing the groove. The stiffener and fiber matt are embedded in a thermoset resin. The thermoset resin is cured to form a fiber reinforced thermoset plastic reinforcement. The substrate is then cross-sectionally cut to form a profile. The profile can be further finished to form a beveled siding for buildings.

Abstract: A plank is disclosed. The plank has a cellular thermoform plastic substrate, a groove formed in at least one planar surface of the cellular thermoform plastic substrate, and a fiber reinforced thermoset plastic backing on the at least one planar surface. The fiber reinforced thermoset plastic backing includes a fiber chord positioned in the groove, a fiber matt placed upon at least a portion of the one planar surface, and a cured strip thermoset resin on the one planar surface in which the fiber chord and the fiber matt are embedded. Planks for siding of buildings and a method of forming the plank are also disclosed.

Abstract: A plank is disclosed. The plank has a cellular thermoform plastic substrate, a groove formed in at least one planar surface of the cellular thermoform plastic substrate, and a fiber reinforced thermoset plastic backing on the at least one planar surface. The fiber reinforced thermoset plastic backing includes a fiber chord positioned in the groove, a fiber matt placed upon at least a portion of the one planar surface, and a cured strip thermoset resin on the one planar surface in which the fiber chord and the fiber matt are embedded. Planks for siding of buildings and a method of forming the plank are also disclosed.