The ground above it was filled in and surfaced over, most likely to provide stable ground in front of a modern bungalow, and the field boundaries that once framed the site have since been removed. What lies below is an archaeological puzzle that was glimpsed briefly in September 1964 and has been effectively inaccessible ever since.

When it was discovered and surveyed by Etienne Rynne, the structure appeared to follow the general layout of a souterrain, an underground passage and chamber built in early medieval Ireland, typically from drystone walling or upright slabs, used for storage or as a place of refuge. The Tinderry example consists of a short entry passage roughly one metre long leading into a narrow creep, the low connecting section just 0.4 metres wide and 0.58 metres high, which in turn opens into a small roughly hexagonal chamber at the northern end. The walls rely mainly on orthostats, large upright stone slabs, with very little drystone infill. The roof of both the entry passage and the chamber had already gone when the structure was examined, though the creep retained its flat stone lintels. The original floor material was darker and grittier than the surrounding sandy soil, suggesting a deliberate mix of clay and small pebbles. What makes the site genuinely unusual is its size. The whole structure is compact to the point of being cramped, and the scholar Manning raised the possibility, noted by Stout in 1984, that it may not have been a souterrain at all but rather a corn-drying kiln, a small stone-built furnace used to dry harvested grain before milling. The two types of structure can be difficult to distinguish, particularly when incomplete, and the Tinderry example sits awkwardly between the two interpretations.