Corbelled construction is an ancient technique in which stones are laid in overlapping courses, each projecting slightly inward, until they meet at the top without the need for mortar or a keystone. Of the five structures that once stood at Cathair Bheag na Máirtíneach, only one survives in any meaningful sense, and even that survivor has been so heavily reworked that the boundary between early medieval fabric and later farm improvement is genuinely difficult to trace.

When John Windele recorded the site in 1848, he counted five huts within the cashel, though only three appeared on the Ordnance Survey maps of the period. By 1899, when the archaeologist Macalister visited, substantial remains of just one hut were standing, with faint traces of others. The surviving structure was probably originally circular and roughly 4.5 metres in diameter, but its eastern half has been largely destroyed and replaced with a straight modern wall. What remains of the western wall is thought to be original, though it has been heightened at some point. The entrance, facing south-east and under a metre wide, leads into a space that has been adapted as a sheep-fold or shelter, and a short wall on the outside of the south-west entrance may have been added specifically to funnel animals inside. One small lintelled recess survives in the wall opposite the entrance, measuring just over thirty centimetres across; a second recess that Macalister recorded is no longer visible. To the east, field clearance debris now covers the area where he noted traces of a second clochaun, the Irish term for these drystone beehive huts, though the connecting passage between the two structures can still be made out beneath the accumulated stone.