This large, Hadrianic fullery consists of two halls, separated by a wall with a door in the west part. Originally a tripartite entrance led to the building to the west. Its north and south part were blocked already during the construction, the central part later.

The north hall consists of a courtyard with a porticus along the north, east and south side. In the south-west corner is a bench flanked by basins (D, G). In the north-west corner a slightly older shrine was found, that was respected in the fullery. Some of its remains are an altar or base of tufa stones, and a black-and-white mosaic with the words:

In the floor of the south room are three very large basins. The water in the northernmost basin flowed to the central basin, and from there to the southernmost one, through lead pipes. The ceiling was supported by three brick piers. Around the basins is a floor of opus spicatum, later partly replaced by travertine.

To the east of the basins are four rooms with terracotta pressing-bowls (six or seven bowls in each room), along the north, east and south side. On either side of the bowls are small walls, which served as hand-rests for the men who wrung the textile with their feet. Another sixteen bowls with hand-rests line the west and south wall of the hall. The imprints of three more bowls were found in the north-east corner of the hall. In the north part of the hall are a basin (A), a small fountain in a recess in the central part of the dividing wall (A1), and a bench (B). Along the west side is a further basin (C).

In 1912 a large quantity of white material was found in one of the bowls. It dissolved in water and then looked like soap. It did not contain organic material and is probably the so-called creta fullonica or fuller's earth.

The location of the fullery, in the north-east part of Ostia, suggests that in the fullery the clothes were cleaned of people working in the harbour for the Imperial government, including the fire-fighters (vigiles).