High Costa Mill And Attached Cottage

An 18th-century watermill with an attached cottage, modernised and extended in the 20th century. The mill, probably incorporating earlier fabric, is dated 1819, as inscribed on a lintel. The cottage is cruck-framed, encased in limestone, and has a pantile roof. The mill is constructed from roughly dressed sandstone with tooled dressings and features a pantile roof and a brick stack.

The cottage is two storeys high with three bays, plus a later projecting bay to the left. The main entrance is at the rear, in an altered outshut. It has large-pane horizontal-sliding sash windows with timber lintels, three-light to the ground floor and two-light to the first floor. A double garage is set beneath an elliptical arch in the left bay, with a 20th-century window above. Internally, a full cruck truss with a saddle apex divides the cottage into two bays.

The mill is of the bridge type, two storeys and an attic, with two wide bays and irregular fenestration. A renewed stable door is on the left, beneath a tripartite lintel with a shield bearing the inscription "1819 IS". A renewed board door is set beneath a similar lintel, partly rendered. A semicircular wheel arch is centrally located, with a two-light window with 12 panes, partly shuttered, to the left. A single two-light, large-pane horizontal-sliding sash is on the first floor, and there are two small shuttered attic windows. The building has coped gables and shaped kneelers, with a stack on the left end. A plank door is on the rear, set beneath a tripartite herringbone-tooled lintel, alongside a wheel arch and a first-floor window. A blocked opening on the right return was likely for the wheel axle of an earlier mill.

Inside the mill, a partly reconstructed undershot wheel with an original timber axle remains. A surviving original square main shaft, chamfered with run-out stops, rises through the first floor to the attic floor. An iron wallower and spur wheel are also present, along with the visible site of one pair of under-driven stones on the first floor. Before 1713, the mill was in the ownership of Thomas Marshall of Aislaby Hall, who later became Lord Mayor of York.