It sits roughly 100 metres east of Creevaghbaun Church, its barrel-vaulted roof intact, its well-dressed mortared limestone blocks still holding firm. The structure measures just 1.8 metres in length and 0.7 metres in width, with a flat-headed doorway on the west end of the north wall that is 0.5 metres wide and 1.1 metres high. Everything about its proportions suggests confinement, purpose, and heat.

The building has been tentatively identified as a sweathouse, a type of early Irish sauna used for therapeutic sweating, typically heated by burning turf inside until the walls absorbed the heat, then raking out the embers before a person crawled in. That cramped entry was usually a deliberate feature, designed to retain warmth. Here, though, the doorway is considered notably large for the type, which leaves its precise original function genuinely uncertain. The limestone blocks themselves may have been salvaged from another structure, suggesting the building was assembled with materials already at hand rather than purpose-quarried. A holy well lies approximately five metres to the north, and the proximity of the two features is suggestive; sweathouses were sometimes associated with sacred or healing sites, and the pairing of well and small stone chamber was not unusual in the Irish landscape.