Buttermill House, Lismore, Co. Waterford

Its roofline has partly collapsed inward, its window openings gape or have been crudely blocked with stone, and its floors sag where timber has finally lost its long argument with damp. Despite all this, the structure holds its shape: an eight-bay, three-storey block over a part-raised basement, built on a U-shaped plan with two projecting end bays flanking a wider central range. It is a working building that has been allowed to fail gracefully, and there is something quietly theatrical about the way ruin has settled over such a deliberately solid design.

The mill dates from around 1790, a period when Lismore's economy leaned on small-scale industry of exactly this kind, processing dairy produce for a local and regional market. Built of random rubble stone bonded with lime mortar, it was designed with three-storey elevations on all sides of its U-shaped footprint, giving it an unusually muscular presence for a building of its function. Round-headed window and door openings, each finished with rough stone voussoirs (the wedge-shaped stones that form the curve of an arch), lend a slightly formal air to what was fundamentally a working structure. Traces of the original timber windows and boarded doors survive here and there, along with fragments of cast-iron guttering clinging to the stepped eaves, evidence of a building that was once fitted out with some care rather than thrown up purely for utility. The hipped slate roofs, framed in timber, have partly given way, and it is this slow collapse, rather than any single dramatic event, that has brought the building to its current state.

What makes the site worth pausing over is less its function, long since ended, than its presence in the landscape. Set back from the road within its own grounds, now overgrown and enclosed by a rubble stone boundary wall, the mill has taken on what might be called a Romantic quality, a ruin that reads almost as a folly even though it began life as a straightforwardly industrial building. It survives as a marker of Lismore's manufacturing past, a reminder that the town's history includes not just its more celebrated architecture but also the working buildings that quietly served the surrounding countryside before falling, slate by slate, into the picture they now present.