Concrete wall related to the latest phase of use of the structure. Rooms 8 and 9 were both backfilled by soprintendenza. The upper halves of wall were left exposed, which could have affected preservation. A few basalt stones and one ashlar block were re-used from earlier phases in the foundation of the wall. The four holes line up with one another on each side of the wall, while only one continues through to the other side. These holes were possibly used to support timber beams for shelving or a ceiling. The gap beside the ashlar block in the foundation could be related to a sewer construction. Flat tufo tiles at the southern end could be related to a channel coming through room 8.