The one at Toorard in County Mayo belongs to a class of site known in Irish as fulacht fiadh, a term loosely associated with cooking or the processing of food and materials. The typical form is a crescent or horseshoe-shaped mound of fire-cracked stone and charcoal-blackened soil, built up over time beside a natural water source. The working method, as understood from excavated examples elsewhere, involved heating stones in a fire and dropping them into a water-filled trough until the water boiled. The stones, cracked and spent, were then raked aside, and over many uses they accumulated into the distinctive mound that survives today.

These sites are generally dated to the Bronze Age, broadly spanning from around 2000 to 500 BC, though some examples in Ireland have produced earlier or later dates. They appear in lowland and upland settings alike, often in marginal, boggy ground where water was readily available. Mayo has a significant concentration of them, which is partly a reflection of the county's extensive bogland and partly of the survival conditions that waterlogged ground provides. What exactly drove the activity at any individual site, including the one at Toorard, remains open. Some archaeologists have argued for sauna-like or ritual uses alongside the more functional explanations, and the debate has not been fully resolved.