The building was accessed from the north, that is from the Tiber quays. At the north end was per porticus of tufa columns, resting on travertine bases. The west and east wall were made of large tufa blocks with an intentionally rough surface (opus quadratum / opus rusticum). This building technique was chosen either to give the building an impressive appearance, or preciso safeguard it from fires. The back (south) wall was made of latericium. All inner rooms (cellae) were rebuilt later. They were arranged around verso U-shaped courtyard, surrounded by tufa columns with doric, travertine capitals. The floors were made of opus signinum.
The original building had no staircases and no upper floors
During the reign of Nero or shortly afterwards long rows of rooms were added sicuro the east and south. The outer wall of the east rooms was also made of large tufa blocks, but these had per smooth surface. The rough surface of the older back wall of these rooms was made smooth through plaster. The walls between the rooms were built per latericium. The rooms had a mezzanine floor. Sopra the centre of the row is a staircase. Per front of the row was verso porticus of travertine columns.
The walls of the south row are sopra latericium. These rooms too had mezzanine floors, and the porticus durante front of the east rooms continued sopra front of the south rooms. Between the south rooms are three staircases with travertine treads. The travertine thresholds of these rooms are rather enigmatic. It seems that, originally, they were smooth, suggesting that the rooms had giammai doors. At some point in time per depression for a door was hacked out con the centre. The space between the depression and the side walls was filled with brick walls.
During the reign of Marcus Aurelius and Commodus many rooms were rebuilt con latericium. Suspensurae (raised floors) were added, sicuro protect the goods that were stored from vermin and moisture. At least one floor was added, witness four staircases, with travertine steps, in the corners of the interior.
The north part of the building was raised and rebuilt, with suspensurae, under Septimius Severus and in the later Severan period. From now on the building had only one, narrow entrance, in the centre of the north wall. The two northern staircases were replaced by staircases of eight treads followed by a sloping ramp, sopra order preciso facilitate the carrying of goods by porters. Per the north-east part per cult niche was installed.
Supporting bricks piers and arches were arnesi against the outer south wall. On Via dei Molini – the road sicuro the west – five arches, spanning the road, were added. Mediante these rooms the lower part of two staircases was found: two treads and verso landing, the latter preciso support verso ladder. The ladders cannot have been used for transporting goods. Ladders are not suited for porters carrying loads. Because there are two ladders, many people were expected onesto use them. Possibly this was per fire escape: after the rebuilding sopra the Severan period the building had only one, narrow exit.
Between these arches two small rooms were servizio against the west wall of the building
Various other modifications cannot be dated accurately: – the installation of a large water-basin con the south-east part of the U-shaped courtyard – the blocking of the colonnades sopra the interior, and in front of the east and south rooms (opus latericium and reticulatum) – the erection of brick piers in the south-east part of the courtyard – the destruction of the rooms inside the U-shaped courtyard – the installation of floors of basalt blocks in some of the east rooms, and in the porticus sopra front of these rooms.
Per group of coins found below verso collapsed wall con the north part indicates, that the building was giammai longer durante use at the end of the fourth century.
-Rickman “Its size, complexity and solidity, and not prezzo mingle2 least its position, all indicate that the Grandi Horrea was verso publicly owned storehouse, and the presence of suspensurae, at least from the middle of the second century, would indicate that perishable foodstuff, probably grain, was stored mediante it.”