This rectangular limestone building, measuring roughly 11.5 metres north to south and 5.55 metres east to west, sits about 15 metres to the south-south-east of the better-known Teampall Bhreacáin, or Temple Brecan. What makes it quietly puzzling is an internal dividing wall that was inserted without being bonded into either the east or west walls, meaning it was added after the main structure was built and was never fully integrated into it. Someone, at some point, decided to partition the space, but did so loosely, as though the arrangement might need to change again.

The building's fabric is roughly coursed limestone masonry, the same material that defines most of the ecclesiastical architecture on Inis Mór, where flat Burren-type stone was abundantly available. Its east wall contains a pointed arch doorway, and directly opposite in the west wall are the remains of a second doorway. To the south of that western entrance is a two-light ogee-headed window, the ogee being a double curve, concave below and convex above, that became fashionable in late medieval Irish ecclesiastical building. Niches are set into the east end of the north wall and the south end of the east wall, likely intended to hold small objects of devotional or practical use. The building is catalogued as Building H in John Waddell's 1973 survey of the complex, which remains one of the more detailed architectural examinations of the Seven Churches group.