Outbuilding to N. of Treginnis Isaf Farmhouse

This is a later 19th-century outbuilding located about 20 meters north of Treginnis Isaf Farmhouse, adjacent to an enclosed yard behind the granary and calf house. Its original purpose is uncertain, but it may have served as a labourer's cottage, as suggested by the sunk slated floors that indicate it could have been a slaughterhouse. The building is constructed of rubble stone and features a hipped slate roof with an off-centre brick chimney.

The outbuilding has a three-room layout and is a single storey. The eastern front has a door with an overlight beneath a timber lintel, flanked by two small windows with cambered brick heads. There is an additional door at the northern end. At the rear, there are three lean-to pig-sties on the left and a small lean-to on the right, which has a door at the southern end. The northern end features an older, roofless gabled privy. The pig-sties have enclosed areas in front and open directly into the enclosed yard.

Inside, the building contains three small rooms with slate-flagged floors. The northern room is windowless and has a low wall that separates a sunken floor from a rear corridor. The central room has both a door and a window, while the southern room includes a window and a small fireplace.

This outbuilding is included for its group value with the farmhouse and surrounding structures.