Former Domestic Range at Plas Isaf

This is a late 19th-century rectangular building, originally part of a larger domestic range at Plas Isaf. It is built of rubble stone with roughly-squared limestone quoins, some original external render and limewash, and a slate roof. A late 19th-century brick chimney stands centrally with oversailing upper courses, and an earlier 19th-century chimney remains in the south-east corner. The north-west gable features an original three-light window to the upper floor, with a chamfered sandstone surround and moulded label, although the mullions have been removed; it has 20th-century glazing. Above this is a segmental relieving arch constructed with rough-dressed voussoirs. A further three-light window is visible on the ground-floor southwest wall, now within a later outshut; its sandstone mullions remain, though the window is blocked. The south-east gable has a former entrance that has been reduced to a two-light window, with an original four-light wooden mullioned window above. There is external stone-stepped access to the upper entrance with a boarded door. The north-east side, facing the farmyard, has an off-centre entrance to the right with a boarded stable door and exposed timber lintel. To the left is an open window, formerly an entrance, with an open wooden frame and exposed timber lintel. The southwest side has a low catslide extension with a central entrance and a 19th-century boarded door, flanked by small four-pane 19th-century sliding sash windows. The northwest return incorporates a reused late 17th-century oak pegged cross-window with surviving leaded quarries to the upper section, believed to have been taken from the main house in the 19th century.

Adjoining the former domestic range to the north-west is a long, low byre addition, built of rubble stone with a corrugated iron roof. This features a 20th-century two-pane window on the left and two entrances to the right; the first with a stable door, and the farthest with a modern steel door.

Inside, the former hall has a beamed ceiling with stopped-chamfered main beams and neatly stopped-chamfered joists. Evidence of mortising suggests a former partition dividing the hall from a cross-passage, originally with opposing entrances. The attic floor is supported by a three-bay pegged collar truss roof, with the south-east truss originally serving as a partition truss. A simple Tudor-arched door-head is cut into the collar.