The four-storey limestone structure, recently restored in 2016-17 with a new roof and reconstructed battlements, showcases the defensive architecture typical of its era. Built from roughly coursed rubble with a distinctive base batter, the tower measures approximately 10.6m by 9.3m, with walls over two metres thick. Local tradition attributes its construction to Mairgread nhee Gearoid, whose “bed” or lookout platform can still be seen atop the keep, though this legend is shared with several other Kilkenny castles.

The castle’s complex ownership history reflects the turbulent politics of medieval and early modern Ireland. According to Carrigan’s 1905 account, Nicholas Shortall died in 1621-22 whilst holding the manor, castle, town and lands of Tibbin, also known as Tibbrudbrittaine. The Down Survey of 1655-6 confirms Robert Shortall as proprietor in 1640, but by 1653 another Nicholas Shortall had forfeited the property to the Earl of Ormond. The castle may have originally belonged to the Ormonds before passing to the Shortalls in the late 16th century, only to return to Ormond control by the mid-17th century. A limestone fireplace on the third floor bears the date 1596, likely marking renovations during the Shortall period, as this feature appears to be a later insertion along with a similar fireplace on the floor below.

The tower’s interior reveals sophisticated medieval living arrangements accessed via separate flights of mural stairs built into the eastern corner. The ground floor, entered through a pointed doorway protected by a machicolation and murder hole, served practical purposes with storage areas and later modifications including a fireplace. The second floor, covered by a barrel vault, functioned as the main living space with elegant stepped shouldered-arch windows featuring stone seats, wall cupboards, and a polished limestone fireplace. The third floor provided additional accommodation with similar amenities, including two-light mullioned and transomed windows and garderobe chambers. Unusually for a tower house of this period, Tubbrid lacks gun loops, suggesting it was built before firearms became common in Irish warfare, relying instead on traditional defensive features like its thick walls, murder hole, and elevated position above the river valley.