It is, in fact, a sweathouse, one of Ireland's more quietly remarkable vernacular building types. Sweathouses were used as a form of folk medicine, functioning on a principle not unlike a sauna: a fire would be lit inside to heat the stones, the embers cleared out, and a person suffering from rheumatism or similar complaints would crawl inside and sweat out their ailments. This one is built in the beehive style, a method of drystone construction in which courses of unmortared stone are corbelled inward until they meet, forming a self-supporting dome. A flat slab closes the roof internally, and a low lintelled entrance faces east, just eighty centimetres high and sixty-five centimetres wide, meaning entry requires crawling on hands and knees.

The structure measures only 1.65 metres across internally, barely enough space for one person to sit or crouch. It does not appear on the Ordnance Survey maps of either 1836 or 1876, which suggests it was either overlooked by surveyors or already regarded as unremarkable by that point, an ordinary piece of rural infrastructure rather than something worth recording. The scholar Richardson, writing in 1939, noted the presence of a chimney nearby, a detail that hints at how the heating process was managed and how the site may have been used in a slightly more organised way than the bare structure alone implies. The stream close by would have served the practical need for water before or after use.