It is known as St Senan's Bed, a name that folds together the sacred and the bodily in a way that distinguishes it from the more conventionally ecclesiastical ruins surrounding it on this island of concentrated early Christian remains.

The building is rectangular, measuring roughly eight metres east to west and just under five metres north to south, and it shares its alignment with the adjacent church, Templesenan. Its walls are rubble-core construction faced with small stones, and the southern wall survives to a height of 1.6 metres. The doorway, set at the western end of the south wall, retains a chamfered surround with pyramid stops, a decorative stonecutting detail in which the angled edge of the jamb terminates in a small raised point, suggesting a degree of craft beyond basic utility. The bases of two window embrasures remain, one in the east wall and one in the south. What makes the structure stranger still is what once stood against its exterior west wall: an ogham stone, one of the upright pillar stones incised with the early medieval Irish script known as ogham, had been incorporated into a seat-like arrangement there. It has since been moved to the island's visitor centre for protection. Roughly three metres to the west, a cross-slab with inscriptions lies on the ground. The antiquarian Thomas Westropp recorded the site in 1897 and again in the early 1900s, placing it within a broader documentation of Scattery's dense cluster of early monuments.

Scattery Island is accessible by seasonal ferry from Kilrush, and the buildings are openly visible once on the island. The ogham stone's former position against the west wall is now empty, but the cross-slab to the west remains in place, and the proximity of St Senan's Bed to Templesenan, separated by little more than a stride, is striking in person in a way that aerial photographs alone do not quite convey.