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 puro give the building an impressive appearance, or puro 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 per niente 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 segno kinkyads in large tufa blocks, but these had a 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 mediante latericium. The rooms had per mezzanine floor. Con the centre of the row is per staircase. Per front of the row was per porticus of travertine columns.
The walls of the south row are con latericium. These rooms too had mezzanine floors, and the porticus durante front of the east rooms continued mediante 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 per niente doors. At some point con time a depression for verso door was hacked out durante 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 in 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, sopra the corners of the interior.
The north part of the building was raised and rebuilt, with suspensurae, under Septimius Severus and con the later Severan period. From now on the building had only one, narrow entrance, per the centre of the north wall. The two northern staircases were replaced by staircases of eight treads followed by verso sloping ramp, in order preciso facilitate the carrying of goods by porters. Con the north-east part a cult niche was installed.
Supporting bricks piers and arches were serie against the outer south wall. On Modo dei Molini – the road esatto the west – five arches, spanning the road, were added. Sopra these rooms the lower part of two staircases was found: two treads and a landing, the latter sicuro support a 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 preciso use them. Possibly this was per fire escape: after the rebuilding mediante the Severan period the building had only one, narrow exit.
Between these arches two small rooms were batteria against the west wall of the building
Various other modifications cannot be dated accurately: – the installation of per large tazza-basin mediante the south-east part of the U-shaped courtyard – the blocking of the colonnades durante the interior, and in front of the east and south rooms (opus latericium and reticulatum) – the erection of brick piers sopra the south-east part of the courtyard – the destruction of the rooms inside the U-shaped courtyard – the installation of floors of basalt blocks sopra some of the east rooms, and in the porticus in front of these rooms.
Verso group of coins found below per collapsed wall con the north part indicates, that the building was niente affatto longer con use at the end of the fourth century.
-Rickman “Its size, complexity and solidity, and not 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.”