Pre-assembled hip, ridge or rake shingle

A hip, ridge or rake shingle is provided, in which a pair of substantially rigid panel portions are connected by a hinge portion, and wherein the shingle is pre-assembled, but can conform to a variety of different angles to accommodate different angular relationships between surfaces of a hip, ridge or rake of a roof. The substantially rigid panel portions are connected by a hinge and may or may not have a reinforcement member, and all of the panels, hinges and reinforcement members are of synthetic thermoplastic polymeric construction and are welded together by ultrasonic or vibratory welding techniques.