Abstract: A method of assembling a sectional upward acting door comprising plural generally planar door panels adapted to be guided between opposed guide tracks. The door panels are provided with hinge assemblies including a hinge plate mounted on the upper edge of one door panel with a pin receiving bore and a cooperating hinge plate with a hinge pin formed thereon mounted on the lower edge of the adjacent panel. One panel may be placed between the guide tracks and suitably supported while the next panel is assembled to the already positioned panel by placing the next panel between the guide tracks and moving it vertically downward to engage the hinge plates on the respective panels. The cooperating hinge plates are configured for snap together engagement which may only be released by intentional manipulation of the hinge plate with the pin receiving bore.