Hen Dyffryn Gwyn

A 1½-storey 3-window house of rubble stone in large roughly dressed blocks and with bigger quoins and boulder footings, under a steep slate roof (replacing original thatch) on a moulded stone eaves cornice and behind coped gable to the L. Of the stone end stacks, the L-hand is original. The entrance is R of centre. It has a round head with thin voussoirs, to double boarded doors. Lower-storey windows have drip moulds. To the L of the entrance is a 3-light mullioned window, above which is inscribed 'HP 1640'. The other windows are replacements in finely moulded surrounds, a 6-pane sash window to the L and 12-pane sash window to the R. Three hipped half dormers have 4-pane horned sashes, and incorporate re-used mouldings in their jambs.

In the L gable end is a shallow rectangular bake-oven projection and prominent boulder footings. An attic window to the R is in a stone surround with moulded lintel, probably re-used, and an inserted attic window is to the L. One of the quoins on the L side is inscribed 'Rice Hughes hoc fecit anno domini 1772'. On the R side the verge bears another inscription 'EE mason 1893'. Continuous with the L gable end is a 1-storey projection behind the house, with flat roof, to a 2-storey former outbuilding, probably originally a brewhouse and farm labourers' accommodation, of rubble stone and slate roof, with 2-pane sash windows in each storey.

The rear of the main range has 2 hipped half dormers with 4-pane sash windows, and an inserted window below the eaves in the centre lighting the stair inserted in the C18. In the lower storey are 2 original window openings with corbelled drip moulds. The R-hand is a 2-light mullioned window and the L-hand has been replaced by a narrower 16-pane sash window.

The entrance opens into a stair hall, with straight stair. To the R and L are timber-framed partitions with reed-moulded studs, and similar detail to the inner sides of the door surrounds. Both screens appear to be original, although the screen on the L side has been partly removed and incorporates re-used materials. On the R side is an C18 fielded-panel door to the parlour and on the L is a replacement door to the kitchen. The kitchen has a central cross beam with ogee stops, and reed-moulded joists. Its fireplace has a stop-chamfered timber lintel on coursed stone jambs. The R-hand jamb has a shallow niche cut into it. To the R of the fireplace is the original stone fireplace stair. In the parlour the fireplace is infilled, but in the rear wall is a window seat with fielded-panel back. Mullioned windows have ovolo internal mouldings.

In the upper storey the room over the kitchen has an ogee door head and a post-and-panel partition with reed-moulded posts. The room has an infilled fireplace, but its corbels and timber bressumer remain visible. Some other first-floor partitions incorporate ovolo-mouldings and are possibly C18. The roof has 2 collar-beam trusses.