Old Plas Cottage including garden walls and gates

Old Plas Cottage is a two-storey house dating from the 18th century, featuring painted stone walls and a Welsh slate gable roof with three stacks, the largest of which is located in the middle, just southwest of the cross-passage. The unpainted southeast gable reveals roughly coursed local limestone rubble walling.

The front elevation has three window bays and a cross-passage doorway, with windows that have timber lintels. The original structure is to the left of the doorway. Starting from the southwest end, there is a three-pane wide window below a 2-light window with small panes above it. Next, there is a 2-light window with small panes on the ground floor and a smaller 2-light window above. Beyond the central stack is an arched stone doorway with a chamfer and stops leading to the cross-passage, featuring a modern boarded door. Following this is a 2-light wooden window on the ground floor, and finally, a small 2-light window with small panes on the first floor. All windows were replaced in the late 20th century. The steeply pitched roof has three rebuilt stacks, and there is a single-storey lean-to at the northeast end with a window and door.

The rear elevation includes a small wing and similar 2-light timber windows on the first floor, along with four late 20th-century attic roof lights. The front garden is enclosed by stone rubble walls, featuring gate piers and 19th-century iron gates.

The interior has not been inspected during the resurvey, but it is reported by the Royal Commission on the Ancient and Historical Monuments of Wales to contain a cross-passage and a northeast ground floor room with stopped and chamfered beams, a window seat, and a stopped and chamfered arched door leading to the stairs by the northeast fireplace, which is covered over.