From the exterior, the building reads as an oval, roughly eleven metres long and just over ten metres wide. Step inside, and the geometry shifts entirely: the interior is rectangular, measuring around five metres by three and a half. That deliberate tension between outer curve and inner angle is not accidental clumsiness but a considered piece of construction, and it is one of the more quietly puzzling features of this type of early Irish building.

The structure is a clochan, a type of dry-stone building associated with early medieval Ireland, typically corbelled to form a roof without the use of mortar. Corbelling works by laying successive rings of flat stones so that each course projects slightly inward over the one below, eventually meeting at the top to form a self-supporting vault or dome. Here, that corbelling still survives at the north-east section of the structure, which gives some sense of how the roof once closed over the rectangular interior space. A doorway opened through the west end-wall. The whole sits on level limestone ground, a characteristic of this part of Connacht where the bare karst pavement shapes both the landscape and the available building material. The interior is now filled with rubble, which obscures much of the lower fabric and makes it difficult to read the full sequence of construction.