Retaining wall visible in room 4 and 5. Robbed on its eastern part. Obviously room 4 has been exposed to robbing more than room 5. Few inclusions - pottery, tiles and tufo slag (medium size). Wall is ashlar blocks standing on bedrock (covered by a fine sandy layer of soil). No binding agent - presence of sandy soil. Ashlar blocks show traces of cutting (horizontal) but, according to Jeff Becker, just traces due to the poor quality of tufo. They show layers of different size grains of tufo.