A taper tool for applying tape to a wall surface is provided. The taper tool may simultaneously advance tape and apply mastic to the advancing tape. The taper tool may include a jam clearing assembly for clearing tape jams occurring along the tape path. The taper tool may include a body for holding mastic and a taper head coupled to an end of the body. The taper head includes a housing defining an opening and a mastic ejection nozzle, both of which are in fluid communication with the body. The opening facilitates introduction of mastic into the body and the nozzle facilitates ejection of the mastic from the body onto the tape. The taper head also includes a valve positioned within the opening to control introduction of mastic into the body, and a cover plate removeably connected to the housing to cover both the opening and the nozzle.