Llwyn-onn, Tanat Valley

Llwyn-onn is a farmhouse, originally dating from the 18th century, with a later 19th-century wing. The original part of the house is built on a downslope and consists of a 1½-storey range, where only the upper domestic portion has a lofted space. The walls are of quasi-rubble slate, except for the north and south gables, which are timber-framed. The east side, originally the front facing the farmyard, is painted white and has random, graded slates, while the west side has corrugated sheeting. The roof has a tile ridge and a mid-chimney that has been truncated just above the ridge.

The upper domestic part of the original range faces east, with a timber lintel over the doorway to the hall, which has a boarded door. There are two dormer windows and two lower windows, slightly misaligned, each with two lights. One dormer has a slated roof, and the other a sheeted roof. A steel window is set within an opening to the rear (west). The lower part of the original range also faces west and has three doorways with timber lintels and boarded doors. The door on the right (south) is a heck door.

The 19th-century wing is attached to the east side and is a two-storey, three-window structure, constructed of similar materials and painted white except for the chimneys. It has one end chimney and one chimney abutting the original house. The wing has windows facing only the front: three-light mullion and transom windows are set under the eaves, and larger windows with segmental arches are below. There are no sills, and the boarded front door has a matching arch.

A stone platform on which the original house stands has been extended to form a front terrace and raised yard for the later wing. Lean-to sheds with corrugated roofing are attached to the gable of the original house; one has been partially filled in with concrete blockwork. Kennels have been built in the extended area in front of the later wing.

The interior of the original range has a central chimney, likely inserted, with a hall to the north. Beyond the hall are two small inner rooms. To the south of the chimney, and at a lower floor level, is a byre, with an end bay that was likely a stable. There are four bays with cruck frames. The first separates the inner rooms from the hall and includes a tongue and groove planked dais partition with two pointed-headed doors; the angle of the cruck forms part of the doorhead shape and the door to the left (possibly leading to a parlour) remains. The second cruck frame is at the chimney position and the third is within the byre.

Access from the original range to the 19th-century wing is via a doorway opposite the chimney, with a short flight of stairs leading up. The later wing is planned symmetrically with a central bay containing the stairs.