This wall functioned as the western exterior wall of the building. It was probably built in one of the later phases of Room 22, since its southern side was built over the ashlar blocks (SU 5825) in that area. The wall is also abutted by the floor SU 5815, suggesting simultaneous use. The northern limit of this wall has degraded, and it may have been cut in a later phase in order to provide access to Room 21; originally it may have continued north as the exterior wall of Room 21.