The building they now ornament is a rectangular limestone ruin measuring roughly nineteen metres east to west and just over eight metres north to south, sitting within the northern sector of a graveyard that itself may occupy the footprint of an older ecclesiastical enclosure. The whole site carries the quiet sense of a place that has been continuously adapted rather than simply abandoned.

The church was built in two distinct phases. The earlier work is visible in the surviving sections of the east gable and the north and south side-walls, where larger limestone blocks set the construction apart from what came later. The west gable, thought to date from perhaps the fifteenth century, was keyed into this earlier fabric, meaning its builders physically interlocked new stonework with the old to tie the addition together. It announces itself architecturally with a pronounced base-batter, a sloping thickening at the wall's foot intended to add stability and resist water, as well as a string course running horizontally across the face. Entry is through a pointed arch doorway with chamfered jambs in cut limestone, and the south wall presents a small sequence of features that repay close attention: traces of a first-floor window near the western end, which suggests there was once a loft or upper chamber in that part of the building; an ogee-headed single-light window set into a segmental arched embrasure further along; and a flat-headed aumbry, a small wall recess typically used to store liturgical vessels, near the south-east angle. By 1552, the vicarage of Caishell had become administratively significant enough that Richard Nugent, Baron of Delvin, was granted a twenty-one year lease of it, and the church appears on an early seventeenth-century map of Rathcline barony under the name 'Cashell & Clame'. Nineteenth-century memorials have since been inserted into the internal faces of the south wall and west gable, folding yet another era into the building's accumulated fabric.