The structure is easy to overlook; what survives is the low double-faced stonework of a roughly D-shaped footprint, measuring about nine metres east to west and eight and a half metres north to south, with faint traces of walls running southward toward the island's ecclesiastical enclosure. Yet what the ground holds is only part of what once stood here.

When the antiquarian R.A.S. Macalister recorded the building in 1896, it was still legible as a two-chambered structure: a southern room of roughly nineteen feet by twelve, and a narrower northern chamber running to twenty-one feet by six. A separate square building to the southwest, noted earlier by the geologist George Henry Kinahan, had already vanished by the time Macalister wrote, and no trace of it has been found since. The date of the house is not established, though its position immediately north of the oratory, and those wall-lines reaching toward the enclosure, suggest it belonged in some way to the wider monastic complex that gives High Island much of its archaeological character. By the time Michael Herity examined the site in the 1970s, the two-chamber plan had dissolved into the single ambiguous footprint that remains today, a D-shape pressed close to the cliff, with the sea not far off.