Sweathouses were a feature of rural Irish life for centuries, used to treat rheumatism and other ailments by heating the interior with a peat fire, raking out the embers, and then crawling inside to sweat in the residual warmth. This one at Gubaveeny is a particularly compact example of the type.

The structure is built entirely of dry stone, meaning no mortar was used, relying instead on the careful placement of stones to hold its shape. Its internal diameter is just 1.5 metres, and it stands 1.65 metres high, roofed over by two large flat slabs in a beehive configuration, a corbelled technique that distributes weight outward and downward rather than relying on a central keystone. The entrance at the south-west is low and narrow, just 0.47 metres high and 0.6 metres wide, roofed by two lintels, the upper of which is now broken. Writing in 1939, a researcher named Richardson recorded a chimney on either side of the structure, details that point to the practical mechanics of heating the space and venting smoke before users climbed in.