What sets it apart at a glance is its T-shaped plan, a form that results from two transepts projecting out from the nave while a shallow chancel closes off the eastern end, giving the building a silhouette that reads as something between a modest country chapel and a more ambitious parish ambition. A sacristy was added to the east end of the chancel at some point, nudging the footprint further still.

The building runs on a conventional east-west axis, as is typical for Christian churches, with the altar end oriented towards the east. Its exterior is rendered, meaning the stonework is covered in a coat of lime-based plaster, though the buttresses, which are set at regular intervals along the walls to provide structural support against outward thrust, are left in exposed stone. The windows are tall with round-headed arches and brick surrounds, a detail that speaks to a more considered budget than a purely functional rural building might attract. A bellcote, a small open stone framework designed to hold a bell without requiring a full tower, sits atop the west gable. Somewhere along the way, a wide opening was cut into the south wall, almost certainly to ease the movement of whatever the building now stores rather than to serve any liturgical purpose.

The church sits within Kilcummin village itself, so it is not difficult to locate. Its current use means access to the interior is unlikely to be straightforward, but the exterior details, the buttressing, the bellcote, the brick window surrounds against rendered walls, are visible from the outside and reward a close look.