The hut is modest in its dimensions, roughly ten metres by six and a half metres internally, but the walls are substantial enough to suggest permanence rather than temporary occupation. At their thickest they reach two and a half metres, and though the interior face stands less than half a metre high today, the exterior still rises to about seventy centimetres. At the southern end, a heap of sod-covered stones adds another layer of ambiguity to the site, its purpose not immediately obvious from what survives.

A cashel is a stone-walled ringfort, a form of enclosed settlement common across early medieval Ireland, typically used to protect a farmstead and its inhabitants. The one at Rannatruffaun is more complex than many. This hut is not the only structure inside its walls: a second hut site occupies the north-east quadrant of the enclosure, and there is a possible souterrain, an underground passage or chamber often associated with storage or refuge, in the same southern half where this hut stands. Together they suggest a settlement with some degree of organisation and perhaps a longer period of use or adaptation than a single-phase site might show. The physical relationship between the hut and the cashel wall, built against it rather than free-standing, implies the enclosure came first and the structure was fitted into it deliberately.