The Temple of the Ship Carpenters was built on top of a fullery. The fullery was excavated in the 1990's, but it had been identified earlier, in 1938-9. It consisted of two courtyards, one behind and one below the temple, surrounded by rooms. The building phases could be dated to the second half of the first and to the second century AD (opus mixtum). It had obviously stopped functioning when the temple was built, during the reign of Commodus.

In the floor of the courtyard behind the temple are four very large basins, communicating with one another, and supplied with water through a lead pipe. The fullery contained at least fifty bowls: large pressing-bowls and smaller bowls in which detergents such as the creta fullonica (fuller's earth) were stored. On either side of the pressing-bowls were small walls that were used as hand-rests. There were no bowls along the back wall, where masonry bases were found, used for beating cloth. In the centre of the back wall is a niche, which contained a statue of a deity.

Plan of the area behind the temple, with the fullonica. From De Ruyt-Van Haeperen 2018, fig. 9.	Plan of the area in front of the temple, with the location of columns, bases and capitals. From De Ruyt 1995, fig. 1.

In the front part of the building 47 columns, 20 bases and several capitals were found, not finished yet. They are of marble from the Greek island Thasos. On some of the columns the name Volusianus v(ir) c(larissimus) was found. They belong to the second half of the fourth or the first half of the fifth century: this man was either Caius Ceionius Rufus Volusianus Lampadius, praefectus Urbi in 365-366 AD, or his nephew, praefectus praetorio in 429 AD. He may have lived in the House of the Dioscures (III,IX,1). The columns were stored here to be used in building projects of Volusianus, one of which was the adjacent Christian Basilica, where columns with his name were used. The fact that many columns were never used may be related to an invasion, such as that by Gaeseric and the Vandals in 455 AD.

The temple complex was entered through a corridor between two shops. In front of the temple is a courtyard surrounded by a porticus with brick piers. The porticus near the entrance is extra wide, and supported by two additional piers. On the floor of the porticus was a black-and-white mosaic with geometrical motifs and a ship (much damaged). In this part of the building inscriptions were found referring to the guild of the fabri navales, the ship carpenters who built and repaired ships. One of the inscriptions, on a base for a statue, is a dedication to Publius Martius Philippus from 195 AD. He was tribune of the guild in Portus and patron of the guild in Ostia. Ostia and Portus each had its own guild of ship carpenters. The guilds had hundreds of members, which suggests that ships were not only repaired in the harbours, but also built.

	P(ublio) MARTIO QVI[r(ina)] PHILIPPO CVRATORI VIAE PRAE[nesti]NAE AEDILICIO CVRVLI V(iatori) Q(uaestori) A[b aer]ARIO TRIBVNO FABRVM NAV[alium Port]ENS(ium) PLEBES CORPORIS [fabrum naval]IVM OSTIENS(ium) QVI[bus ex s(enatus) c(onsulto) coire li]CET PATRONO [optim]O S(ua) P(ecunia) P(osuit)
EDR074048. Photo: EDCS.

The temple was built on a high podium, and was reached along marble steps. In the front part of the podium, below the pronaos, was a room that could be reached through a door in the left side wall. In front of the temple, in the courtyard, was a rectangular basin. The area behind the temple (c. 16 x 14.50) was flanked by porticoes and could be used by the guild as meeting-hall.