Map of the caldarium in Lucetia's bath.

Dessin © D. Busson et V. Charlanne.

After the warm room, customers had no choice but to head for the southern part of the building-the hot section where all of the rooms were built over hypocausts.

On three sides of the first room were exedra. These served either as sweat benches-which means that the room was a dry hot room (a first stop before the hot rooms)-or as bathtubs.
These exedras were heated by two large furnaces to which were attached service area, which could also be interpreted as saunas.

Three doors in this room led to a room that was heated by a hypocaust and by a furnace located below. The next room was a tepidarium that led, via a double door, to two more hot rooms that were particularly luminous and open, also heated by furnaces in the basement.