The structure is not a single coherent ruin but a layered one, where stones from older phases of construction were reused as later builders needed them, and where a doorway jamb appears to have been lifted from a nearby castle and pressed into service in a mill wall. That kind of quiet recycling is easy to overlook, but here it leaves a visible record of how materials moved between sites across centuries.

The mill was recorded as an 'Old Corn Mill' on the first Ordnance Survey six-inch map of 1843, but by the time of the 1952 to 1953 revision it had disappeared from the cartographic record entirely, suggesting it had fallen out of use and into ruin by then. Its origins may reach back considerably further. The Civil Survey of 1654 to 1656, a mid-seventeenth-century assessment of landholding and property carried out following the Cromwellian conquest, mentions 'two Mills on the River Shewer in repaire', and this building is thought to be a possible candidate for one of them. The rectangular structure, roughly twelve metres by four and a half, is aligned northeast to southwest and built from uncoursed limestone rubble, with walls ranging from 0.6 to one metre thick. A millrace, the channel that directed water onto the wheel, runs along the northwest face, and inside the building a rectangular pit near the west end once housed the inner mechanism of the water wheel, which remains intact. The northeastern wall is noticeably thicker at 1.25 metres and extends beyond the outline of the present building, suggesting it belongs to an earlier phase of construction. Set into it is a small flat-headed limestone window with chamfered edges and hammer-tooled drafted margins, the kind of careful stonework that points to a more substantial original context. About 200 metres to the southwest stood Beakstown Castle, and the chamfered door jamb incorporated into the mill's northwest wall is believed to have come from there, carrying a fragment of the castle's fabric into a working agricultural building some time after the castle itself had ceased to matter.