Abstract: A continuous process for making a structural foam panel with a stiffener is described, and a continuous assembly line for the process is described. The continuous assembly line includes decoilers for decoiling top and bottom skins, uncoilers for releasing top and bottom stiffeners, straighteners for threading and attaching the stiffeners to the skins, respectively, roll formers for shaping both skins and stiffeners into a structural shape, a foam injector for injecting foam between the skins to form an integrated continuous panel, a foam conveyor for pressing the integrated continuous panel, an oven for curing the integrated continuous panel, a clamp and cut-off saw for cutting the continuous panel, and a computer to control the saw to cut the continuous panel into selected kits of discrete panels to assemble selected buildings.