Abstract: A structural wall apparatus includes a plurality of building panels disposed in edge to edge relationship with each panel being connected to the adjacent abutting panel. Each panel has outer and inner metal skin spaced by an intermediate insulating core of foamed polymer. Each panel has at least one interlocking edge having a metal lined tongue and a metal lined groove shaped for each metal tongue to fit into opposing grooves on abutting panels for interlocking the panels together. Each panel has an elongated reinforcing member positioned adjacent the interlocking edge of the panel and has a channel formed therein shaped to fit around the metal lined groove portion and also has a skin attaching flange on one side for attaching the reinforcing member to the metal skin and a strengthening flange portion on the other side of the metal lined groove.