Known today as the Glebe House or sometimes the Abbot’s House, this National Monument has been variously interpreted as a seminary, an abbot’s residence, or perhaps the home of a medieval bishop. The building offers a fascinating glimpse into how ecclesiastical architecture evolved over several centuries, with its mix of 13th-century hall-house design and later tower house modifications.

The original structure was a substantial rectangular hall-house, measuring about 16 metres east to west and nearly 7 metres north to south. Built most likely in the 13th century, it featured a rather grand first-floor entrance accessed by an external wooden staircase; only the beam slot that once supported this staircase remains visible today. The ground floor was a utilitarian space lit by narrow slit windows, whilst the first floor boasted elegant two-light windows with cusped and pointed arches, suggesting this upper level served as the main living quarters. The contrast between the defensive ground floor and the more comfortable upper storey reflects typical medieval building practices for high-status residences.

Later medieval renovations dramatically transformed the eastern portion into something resembling a three-storey tower house, complete with a new ground-floor entrance featuring a pointed arch doorway. These alterations, along with modern restoration work that added a gabled roof and crenellated parapet to the eastern half, have created a building that reads like an architectural timeline. The structure once featured rectangular projections on both its north and south walls, though only foundation lines remain of the southwest projection. As part of the monastic complex at Kilmacduagh, this building stands as a testament to the enduring importance of this ecclesiastical site through the centuries, now protected under the National Monuments Acts.