The two buildings together occupy barely more space than a modest cottage, yet the main church, Templesenan, repays close attention. Its doorway arch is a patchwork of three different materials, Dundry stone, Old Red Sandstone, and slate, arranged with what seems like deliberate care. The eastern window is similarly composed, its arch stones mixed and decoratively ordered. The east wall, meanwhile, leans outward above the window in a way that feels faintly precarious even now.

The building is a nave and chancel church constructed as a single structure, though time has treated the two parts very differently. The nave walls survive to something close to their original height, while the chancel walls have been reduced to around 1.6 metres, and the chancel arch, which once had piers with double and triple mouldings and a central pilaster, is worn down to its base stones. Corbels at the western ends of the north and south walls indicate there was once a gallery overhead. Scholars argue that the church, dedicated to St Senan, the early medieval saint associated with the island's monastic foundation, was rebuilt during the later Middle Ages. The pointed doorway and the segmental rear-arch of the south window point to this later phase, but the builders appear to have incorporated stonework from an earlier structure, possibly salvaged from elsewhere on the island, which helps explain the varied materials visible in the arches. This analysis was set out by Ní Ghrádaigh in 2006, drawing on earlier observations by Westropp at the end of the nineteenth century.

Templesenan lies roughly 140 metres northwest of the island's cathedral, along the same ridge. The small structure immediately to the west, St Senan's Bed, is a feature worth examining in its own right once you are standing there: its precise relationship to the church beside it remains part of what makes this corner of Scattery Island quietly puzzling.