Its castellated roofline and round tower on the north-west corner give it the appearance of a fortified residence with medieval roots, yet no earlier castle is known to have stood on the site. The martial silhouette is essentially a costume, a nineteenth-century remodelling that dressed an older structure in the fashionable Gothic Revival idiom of the period.

The building beneath the battlements is an eighteenth-century house, reworked during the following century into its present five-bay, two-storey form. Castellated country houses of this type were common in Ireland from roughly the 1790s onwards, when landowners across the island began adding towers, turrets, and crenellations to existing or newly built residences, partly for aesthetic reasons and partly to project an air of antiquity and permanence. At Kilcaskan, that process involved retaining the bones of the Georgian house while wrapping it in the trappings of a castle it never was. The round tower at the north-west corner is particularly characteristic of this approach, anchoring the composition and reinforcing the mock-fortified effect. Healy, writing in 1988, identified the building's eighteenth-century origins and its later transformation, and no evidence has since emerged of any genuine defensive structure predating the house on this spot.