This structure is an east-west running concrete wall, faced with petit appareil. The wall functioned as the northern limit of rooms I-10 and I-18; it also seems to have functioned as the southern limit of the series of rooms to the north of the area that remained unexplored in the 2017 season. The southern facade of the wall was different in both rooms, suggesting that these rooms had different functions. In room I-10, the wall was lined with a layer of opus signinum, which is typically used as a water-resistant material. In room I-18, the facade bore notches, evenly spaced and in alignment with the tops of the "stairs" (SU 8246) in the northeast corner of the room. Notches are visible at the same height on the western and eastern walls, which suggests that some structure or decoration was once located here. This was either made of wood, which has since decayed, or stone, which has since been robbed.