Abstract: A building wall comprises channel-shaped uprights and metal-clad insulating panels arranged in alternating sequence so that the interior faces of the panels form parts of the interior walls of the building while the exterior faces of the panels form parts of the exterior walls of the building. Flanges are formed along the vertical edges of the sheet metal outer faces of the panels. These flanges extend into the open sides of the channel-shaped uprights and are situated in facing relationship with the inner faces of the uprights. Vertically aligned lances, struck out from the opposed plates of the channel-shaped uprights, are engaged with L-shaped slots of the flanges of the panels. The lances have camming surfaces which tightly urge the flanges of the panels against the inner faces of the side plates of the uprights so that the flanges and uprights reinforce each other to form a strong, rigid wall structure.