A buck panel adapted to be interconnected with other panels to form a buck to frame a bulkhead or an opening in a wall for receiving a window or door, the buck panel comprising: a foam portion having an internal surface, an exterior surface, a first end, a second end opposite the first end, a first side, a second side opposite the first side, and a center portion positioned between the first side and the second side; characterised by: a central support beam positioned longitudinally within the center portion of the foam portion, the central support beam having a first edge, a second edge, a plurality of plates extending between and connected to the first edge and the second edge, and a plurality of wings extending from the first edge and the second edge perpendicular to the internal surface of the foam portion in such a way that a portion of the wings protrude from the internal surface of the foam portion so as to be received in concrete poured over the internal surface; a first lateral support beam positioned longitudinally within the foam portion near the first side of the foam portion and spaced from the central support beam, the first lateral support beam having a first edge, a second edge, and a plurality of plates extending between and connected to the first edge and the second edge; and a second lateral support beam positioned longitudinally within the foam portion near the second side of the foam portion and spaced from the central support beam, the second lateral support beam having a first edge, a second edge, and a plurality of plates extending between and connected to the first edge and the second edge. a foam portion having an internal surface, an exterior surface, a first end, a second end opposite the first end, a first side, a second side opposite the first side, and a center portion positioned between the first side and the second side; characterised by: a central support beam positioned longitudinally within the center portion of the foam portion, the central support beam having a first edge, a second edge, a plurality of plates extending between and connected to the first edge and the second edge, and a plurality of wings extending from the first edge and the second edge perpendicular to the internal surface of the foam portion in such a way that a portion of the wings protrude from the internal surface of the foam portion so as to be received in concrete poured over the internal surface; a first lateral support beam positioned longitudinally within the foam portion near the first side of the foam portion and spaced from the central support beam, the first lateral support beam having a first edge, a second edge, and a plurality of plates extending between and connected to the first edge and the second edge; and a second lateral support beam positioned longitudinally within the foam portion near the second side of the foam portion and spaced from the central support beam, the second lateral support beam having a first edge, a second edge, and a plurality of plates extending between and connected to the first edge and the second edge. a central support beam positioned longitudinally within the center portion of the foam portion, the central support beam having a first edge, a second edge, a plurality of plates extending between and connected to the first edge and the second edge, and a plurality of wings extending from the first edge and the second edge perpendicular to the internal surface of the foam portion in such a way that a portion of the wings protrude from the internal surface of the foam portion so as to be received in concrete poured over the internal surface; a first lateral support beam positioned longitudinally within the foam portion near the first side of the foam portion and spaced from the central support beam, the first lateral support beam having a first edge, a second edge, and a plurality of plates extending between and connected to the first edge and the second edge; and a second lateral support beam positioned longitudinally within the foam portion near the second side of the foam portion and spaced from the central support beam, the second lateral support beam having a first edge, a second edge, and a plurality of plates extending between and connected to the first edge and the second edge.