Abstract: A fire retardant cover is disclosed herein for covering a ceiling-side recess of a fluted roof deck and for providing a flat surface for installation of a head-of-wall track (associated with a steel stud wall assembly). The fluted roof deck has an undulating bottom surface that defines a plurality lengthwise recesses corresponding to a plurality of ceiling-side flutes of the fluted roof deck. The fire retardant cover is substantially flat and configured to sealingly cover at least one of the plurality of lengthwise recesses. The fire retardant cover comprises a piece of sheet metal bent to define first and second upwardly extending protrusions. The protrusions are spaced apart from each other by a substantially flat web section and have laterally facing outer top surfaces matched to sealingly contact lengthwise bottom surfaces of one of the plurality of recesses of the fluted roof deck when the fire retardant cover is installed.