Abstract: A structural support member for use in a roof deck system that is supported on an upper surface of a roof deck support structure. The primary embodiment comprises a substantially vertical outer segment, a substantially horizontal lower segment connected to the outer segment, a substantially horizontal upper segment connected to the outer segment, a substantially horizontal intermediate segment connected to the outer segment between the upper and lower segments, and a substantially vertical inner segment connected to the intermediate segment and the lower segment. The lower segment is secured to the upper surface of the support structure and supports a metal deck. The upper, intermediate, and outer segments form a C-shaped cavity for receiving the end of a barrier material, such as insulation or concrete, which is supported on the metal deck. The lower, intermediate, inner, and outer segments form an elongated channel that preferably has a plurality of vent holes therethrough.