Though not visible from ground level, what remains of this structure tells the story of a modest defensive residence, likely constructed during a period when protection was paramount. The surviving south gable and partial west wall, along with a projecting tower on the southwest corner, stand as testament to the building's defensive purpose; the tower features ground floor musket loops on both its south and west faces, narrow slits measuring just two inches wide and about seventeen inches high that allowed defenders to fire upon approaching threats whilst remaining protected.

The construction details reveal the practical building methods of the time. The gable wall, rising to approximately 35 feet in height, was built from rough stones that were plastered on the interior and roughcast on the exterior. Small rectangular windows with wooden frames punctuated the south wall at both ground and first floor levels, and remarkably, the marks of these wooden frames remained visible in the roughcast during the Irish Tourist Association's 1942 survey. The walls themselves were substantial but not excessive; the south wall measured just over two and a half feet thick, whilst the tower projected three and a half feet from both the south and west walls, creating a defensive position that could cover two approaches to the house.

By the time of the 1835 Ordnance Survey, the structure was already marked as 'Roscore House in Ruins', suggesting it had fallen from use relatively quickly, perhaps abandoned after the political upheavals of the late 17th and early 18th centuries. The eastern and northern walls had been removed by 1942, though a corner incorporated into a more modern house may represent part of the original east wall near the northeast corner. Archaeological evidence suggests there may have been additional defensive features, including possible traces of a bawn, or fortified enclosure, indicated by mortared field walls to the east of the main structure. The entire castle measured over 33 feet in length, making it a relatively compact fortified dwelling typical of minor gentry or prosperous farmers seeking security during uncertain times.