Cow Byre and Mill at Plas yn Blaenau

The Cow Byre and Mill at Plas yn Blaenau is a 2-storey vernacular building, oriented north-south, built into a change in ground level. The corn mill building is attached to the north end of the byre and stands at a right angle to it. The south gable wall of the byre is adjacent to a flight of stone stairs, with a separately listed byre range nearby. The byre is accessed from the east side at yard level, while the upper floor, used for storage, is entered from the west side at the higher garden level. It is constructed of colourwashed local stone rubble with slobbered mortar and features a gabled slate roof with a clayware ridge. There are three entries on the east side, each with a single hardwood lintel supported by two intermediate stone piers, and the lintel extends south over a small casement window. Above, there are two symmetrically positioned casement windows, and a boarded door leads to the upper floor on the west side.

The corn mill is also built of local stone rubble, with pebble-dash render on its elevations and a gabled slate roof with a clayware ridge. It has entries at the lower level from the north and east, and at the upper level from the south, featuring boarded doors and wooden casement windows. A clayware conduit that carried water from the millpond to operate the mill enters the building on the south side.

Inside, the byre has an open rafter roof with through purlins and trusses with raking struts, resembling that of a farmhouse. The upper floor structure is framed in hardwood. The corn mill has an open rafter roof with through-purlins and king-post trusses, along with secondary raking struts. A date of 1832 is painted on the tie beam. An iron staircase leads from the lower floor to a landing at the upper (garden) level. Remnants of water-driven corn milling machinery can be found adjacent to the west wall, including a timber launder that enters the building at upper floor level on the south side, an overshot iron wheel with wooden buckets, a cast iron pit wheel, a wallower, and line shafting components.