Prevent combustion spread structure of building facade and a construction method using the same

PURPOSE: A structure for preventing a fire in an exterior wall of a building from spreading and a construction method of an exterior material for preventing a fire in an exterior wall of a building from spreading are provided to prevent a fire in an exterior wall of a building from rapidly spreading by preventing an airstack effect. CONSTITUTION: A structure for preventing a fire in an exterior wall of a building from spreading comprises an exterior material mounting bracket(100), an exterior material(200), a fixing bracket(300), a cutoff member(400), and a sealing member(V). The exterior material mounting bracket comprises an anchor(110) and a mounting piece(120) coupled to the end of the anchor. The exterior material comprises a finishing panel(210) and an insulating material(220) installed on the rear surface of the finishing panel. The fixing bracket comprises first and second coupling pieces. The cutoff member cuts off the vertical space(S) between an exterior wall of a building and the exterior material. The sealing member is spread on the cutoff member, the fixing bracket, and the gap between the fixing bracket and the exterior material.