The northern walls measure around one metre thick, whilst those to the south are considerably bulkier, possibly because they once incorporated the kitchens. A single gun loop remains visible in these formidable walls, a reminder of more turbulent times when such fortifications were essential for country houses. Unlike many defensive structures of the period, the house lacks vaulted ceilings, and the walls above the basement level are noticeably narrower than those below.

The original house is believed to have faced east, though subsequent additions and alterations have obscured much of its initial layout. These later modifications, dating from the early eighteenth century onwards, can be distinguished from the original structure by their less substantial construction. The defensive features suggest this was once more fortress than family home, built during an era when Irish landowners needed to protect their properties from potential threats.

Today, visitors can still trace the evolution of Altamont House through its architecture, from its thick;walled beginnings to the more refined additions that transformed it into a country residence. The surviving gun loop serves as a tangible link to County Carlow’s contested past, when even domestic buildings required military considerations in their design.