Abstract: A wall panel of the type having two outer sheathing boards separated by rigid foam insulation has a continuous top header and a base reinforcement which are also each formed of two boards separated by rigid foam insulation. Vertical stud members formed of elongated boards have a central web extending between the boards of the top header and of the base reinforcement, and have side flanges nailed and bonded to the sheathing boards and extending between the bottom of the header and the top of the base reinforcement. The stud flanges allow nails to be applied internally of a flange into a first of the outer sheathing boards. The wall panels may have window and door openings cut out underneath the header after the foam has hardened between the panels.