A fulacht fia, as these features are known in Irish archaeology, is essentially an outdoor boiling place: a trough filled with water, heated by dropping stones from a nearby fire directly into the liquid. The process is surprisingly efficient. The spent, fire-cracked stones accumulate in a characteristic horseshoe-shaped mound around the trough, and it is that shape, low and dark and often damp, that betrays these sites across the Irish landscape.

The Clashroe example was excavated in 1985, with the results published by Hurley in 1987. Before any digging began, the site presented as a horseshoe-shaped mound of burnt material measuring roughly 8.2 metres north to south and 5.6 metres east to west, rising to about half a metre in height, with a central depression opening to the west. Excavation uncovered the trough itself, a vessel 1.8 metres long and 0.6 metres wide, hollowed almost entirely from a single oak trunk. A groove cut at the eastern end was designed to hold a closing plank, with a small perforation beneath it that may once have held a wooden peg, suggesting the trough could be sealed or drained. To the northeast lay the hearth, a shallow depression packed with black soil, ash and charcoal, with a spread of that same dark material running from the fire to the lip of the trough. Beneath the charcoal layer, excavators found eleven stake-holes in the ground, possibly the footprint of a roasting spit, which hints that cooking here was not limited to boiling. Radiocarbon dating placed the oak of the trough at approximately 3490 ± 35 BP and the hearth charcoal at 3370 ± 35 BP, broadly consistent with the Middle Bronze Age. What makes the location particularly striking is not the site in isolation but its context: four more fulachtaí fia lie within 60 metres of this one, clustered to the south and southeast, suggesting that this boggy streamside spot was returned to repeatedly, or used by a community rather than a single household.