"The large bathhouse. Elaborately built, it probably served the guests and senior officials of Masada. It consisted of a large courtyard surrounded by porticos and several rooms, all with mosaic or tiled floors and some with frescoed walls. The largest of the rooms was the hot room (caldarium). Its suspended floor was supported by rows of low pillars, making it possible to blow hot air from the furnace outside, under the floor and through clay pipes along the walls, to heat the room to the desired temperature." from www.jewishvirtuallibrary.org/jsource/Archaeology/Masada1....