It is, in fact, the remains of a sweathouse, a small domed chamber used in Irish folk medicine, typically heated by burning turf or timber inside until the walls were thoroughly warm, then cleared of ash and lined with rushes or straw so that a person could crawl in and sweat out ailments. The roof of this example is gone, leaving the outer mound, which measures just over five metres across, open to the sky.

The structure was recorded in detail as part of the Heritage Council funded Munster Sweathouse Project in 2009. Surveyor Harte found the chamber to be roughly circular in plan, measuring approximately 1.96 metres north to south and 2.2 metres east to west on the interior. The walls are built in drystone technique from local grey rubble sandstone, without mortar, and the floor sits lower than the surrounding ground level, a deliberate feature that would have helped retain heat and made the low entrance easier to seal. That entrance, a gap just 0.55 metres wide on the west-northwest face, is now broken down, but its position and dimensions are consistent with original construction rather than later damage. The walls still stand to an average interior height of around 1.5 metres, reaching 1.8 metres on the east side. Built directly onto rock outcrop, the chamber may originally have been covered by a corbelled roof, a technique in which stones are laid in progressively overhanging courses until they close at the top, common in vernacular stone structures across Ireland and needing no timber or mortar to hold together.