Abstract: A modular type building panel for either vertical or horizontal positioning is provided having a hinge element incorporated to facilitate assembly of the panels. The building panels are of a double walled construction having tongue and socket edge configurations adapted to mechanically interlock when placed in assembled relationship with an adjacent panel. The hinge elements comprise a hinge socket and a hinge pin formed with the respective tongue edge portion and the socket edge portion. The hinge socket is disposed adjacent the upper end of the panel as is the hinge pin which permits interfitting of the two elements during the initial stage of panel assembly thereby providing a support pivot facilitating swinging of two panels into assembled relationship. In one embodiment the hinge socket opens at the longitudinal end of the panel for panels designed for vertical walls.