At just 87 centimetres high and 36 centimetres wide, the entrance to this structure in the townland of Reagoulane is barely wide enough to squeeze through crouching low, and that is entirely by design. This is a sweathouse, one of Ireland's more quietly remarkable vernacular structures, and the restricted opening was part of how it worked: once a fire had been lit inside to heat the walls and floor, the narrow mouth helped trap the accumulated warmth after the embers were cleared and a person crawled in to sweat.

Built into a south-facing slope in an area known locally as Poulgorm, the structure sits close to a small stream that runs northwest to southeast into the Multeen River, roughly twenty metres to the southwest. That proximity to water was deliberate. After the intense heat inside, users would plunge into the cold stream as part of the therapeutic process, a practice recorded across rural Ireland well into the nineteenth century as a remedy for rheumatism and other ailments. The sweathouse itself is a corbelled structure, meaning the dry-stone walls are built with each successive course of stone projecting slightly inward until the courses meet at the top, forming a self-supporting roof without mortar. The technique is ancient and robust. Here, the corbelling is capped by a single large capstone, now cracked, which sits at an external height of two metres. Internally the space measures roughly 1.59 metres north to south and 1.54 metres east to west, with a ceiling height of just under two metres, giving enough room to sit upright but no more. The walls are 75 centimetres thick, which would have held heat effectively once the chamber was properly fired.