Patent ID: 8793947

Claim:
A fire-retardant wall system, comprising: a horizontal ceiling element; a plurality of vertical wall studs; a header track for receiving the wall studs, the track connected to the horizontal ceiling element, the track comprising a web and a pair of spaced-apart flanges extending in the same direction from opposite edges of the web, each of the flanges having a first planar portion proximal the web and a second planar portion distal the web; at least one surface on the web for accepting a fire-retardant material strip thereon; at least a first fire-retardant material strip attached to the at least one surface on the web and configured to expand when exposed to elevated heat, the first fire-retardant material strip positioned between and contacting both the web and the horizontal ceiling element to create at least a substantial seal inhibiting the passage of air from one side of the track to the other side of the track through a gap between the horizontal ceiling element and the web when the fire-retardant material strip is in an unexpanded state; at least one piece of wallboard supported by the wall studs, wherein the wallboard is in direct contact with the first planar portion of the flange, and wherein the second planar portion of the flange is recessed inwardly from the first portion, such that the wallboard is not in direct contact with the second portion, the wallboard having an upper edge that is spaced from the horizontal ceiling element to define a deflection gap therebetween; a compressible backer rod positioned within the deflection gap between the upper edge of the wallboard and the horizontal ceiling element; a combination of joint compound and joint tape applied to the wallboard and covering the deflection gap to enclose the compressible backer rod between an outwardly-facing surface of one of the pair of flanges and the combination of joint compound and joint tape.