The walls were constructed by first digging a pit and lining it with large upright slabs, then building slightly corbelled courses of flat slabs on top, a corbelled roof being one where successive courses of stone project inward until they meet overhead. The result is an interior that sits below the surrounding ground level, with the outer faces of the southern and western walls flush with the earth outside. The house measures roughly 2.3 metres east to west and 3.1 metres north to south internally, with a narrow paved entrance passage in the north wall and a window opposite it in the south wall, now reduced to a ragged gap. It shares its eastern wall, which at 1.3 metres wide is noticeably broader than the others, with an adjoining house, though there is no internal doorway connecting them.

The house was excavated in 1938 by the art historian and archaeologist Françoise Henry, who identified it as House C within a cluster of structures on the Bailey Mór, a mound on whose north-eastern slope the buildings sit. Henry found the interior filled with sand, the uppermost layer dense with large fallen slabs that she took to be the collapsed remains of a corbelled roof. Beneath the sand, the excavation uncovered a probable sleeping area in the north corner, defined by low upright stones, and two large hearths superimposed one upon the other at the centre of the room. The west and south corners were packed with seashells. Among the finds were a stone basin, an iron dagger, iron nails, a bone comb, a possible spindle-whorl, and a fragment of whale shoulder blade. Faunal remains were notably varied: cattle, sheep, pig, hare, fish, seal, crab, sea-urchin, a small cat, pony, and bird bones were all recovered from different layers. Charcoal from the lower hearth included ash, hawthorn, and birch. A later radiocarbon date obtained from hazel charcoal, as part of a research project re-evaluating Henry's excavations, returned a calibrated date of AD 1175 to 1269, placing occupation firmly in the later medieval period.