Though this wall is constructed of tufo ashlar blocks like the rest of the earliest phase of the complex, its position makes its phasing difficult to understand. Its position in the middle of room 19, and its placement on top of a slab floor (with no evidence of a construction cut or foundation around it) suggests that it was added after the first phase of the building was complete. Its construction may be associated with the re-use of the space for production purposes (see orange circular "fire feature" SU 5720).