The archaeological excavations in the 1980s revealed the structure of the thermal baths. What was discovered is that the building is built on two floors:  the first is underground and the other one includes the usual thermal spaces (frigidarium, tepidarium, pool).
The underground space is accessible through an entrance located on the eastern side of the central corridor. It is composed of a central corridor, oriented northwest, from which three passages branch off, and with the sewer system under them.
The presence of an exhaust manifold, composed of two pipes and placed along the northern wall of the central corridor, east/west oriented and used for changing the waters of the space above (the frigidarium), lead ust to understand that underground there was the sewerage system.
The underground area was used as storage to take care of the heating system and to feed the services to the thermal spaces, as we deduce from the circular space corresponding to the laconicum and the hole near the tepidarium.
The technical installation has been partially excavated; there are spaces totally hidden still.
In the inside space there are many wall structures (walls in calcareous stone not squared near the tepidarium) that represent the foundation walls of the Santa Chiara complex.