That combination, a roofless shell that is structurally almost complete but ecologically reclaimed, gives the ruin a peculiar quality. The church is recorded under the Irish name 'Tampull Oen Bryn', and by 1700 a contemporary account noted that the roof was still up but the timbers beginning to decay. Within a generation or two, the building had passed from declining parish church to burial ground, with inscribed headstones inside the walls dating from 1719.

The fabric of the building repays close attention even from outside. The south wall doorway retains its dressed limestone jamb stones with chamfered edges, and two curved limestone blocks lying in the threshold are the remnants of what was once a pointed arch above it. Beside them, broken on the ground, is a small stoup or font, the kind of stone basin used to hold holy water at a church entrance. The windows show a mixture of forms: a flat-headed light near the east end of the south wall, and an ogee-headed light, its curved and pointed profile typical of late medieval Irish ecclesiastical work, in the centre of the east gable. Against the outside of the south wall stand two chest tombs, the burial place of the Archdeacon family of nearby Monkstown Castle, their Latin inscriptions now considerably worn. A small rectangular structure built asymmetrically against the outside of the west gable was for some time interpreted as the base of a tower, but is now thought more likely to have been a family burial enclosure.

The church sits at the north corner of the graveyard, which continues to be used and is therefore accessible. The stonework in the doorway, including those displaced arch voussoirs and the broken stoup, is visible without entering the overgrown interior.