Fulling, sometimes called tucking, was the process of cleansing and compressing freshly woven cloth by pounding it in water, and the mills that carried it out were a common fixture of river valleys across early modern Ireland. This one is still labelled on the 1842 Ordnance Survey six-inch map under its older name, tuck mill, complete with the millrace that fed it.

What survives is a two-storey rectangular structure roughly eleven metres long on its north-east to south-west axis, built from roughly-coursed limestone blocks. A projection at the south-west end of the north-west wall hints at a more complex original layout than the ruined shell now suggests. Inside, a dividing wall once split the building into two rooms, each with door openings at both ground and first-floor level. The southern room, the larger of the two, retains blocked arches in the north-east ends of its walls, the points where the millrace, drawn from a bend in the Awbeg about 450 metres upstream, ran through the building to power the mill machinery. The northern room is slightly narrower, with a door opening in the north-west wall. The millrace itself was not a short channel; it was engineered to travel the best part of half a kilometre before reaching the mill, a considerable investment of labour that speaks to how seriously this kind of cloth-processing operation was taken. Another tuck mill stood roughly 650 metres to the east, suggesting that the Awbeg here supported something of a small industrial corridor along its banks.