The present invention describes a fire stop system for wall board construction. The patent addresses the problem of a gap between the head of a wall and a metal fluted deck. Described here-in is a fire resistance assembly made of multiple components of: a fire stop panel and a mounting channel. The fire stop panel or wall has a wallboard geometry manufactured to match the contour shape of a metal fluted deck in a "cookie cutter" fashion. This provides the advantages of saving time and material of wallboard construction, with a product that is novel, simple, and easy to manufacture and implement. The mounting channel of the fire stop system provides for an effective way to provide compliance of the stresses from the roofing/ceiling deck's stresses, easy assembly of the fire stop system, while allowing for a meeting of the fire safety rating.