Old farmhouse at Plas Cemlyn

The Old Farmhouse at Plas Cemlyn is a 17th-century, three-unit in-line range with a stepped roofline. It features a two-storey former farmhouse on the left, a cartshed in the center, and a cowhouse on the right. The walls are made of rubble with slobbered and pebbledashed mortar, and there are stone lintels. The gable coping is rendered slate. A gable end chimney is located to the right of the house part, complete with capping. The pitched roofs are covered with small slates arranged in reducing courses.

The farmhouse has a boarded door on the right and a horizontally proportioned window to the left, with a narrower window above it. There is a single window on the center of the rear elevation. All windows have modern timber frames with small panes. A low stone staircase is positioned against the right gable of the house, leading to the first floor. The cartshed, which is stepped down to the right, has a lower roofline and features a single wide boarded door. The cowhouse on the right end has a door to the right and a small window to the left, along with a similar window on the right end of the rear elevation, both of which were former ventilation slits. There is a blocked window on the gable end. The building is situated within a stone-walled yard.

Inside, the main door opens into a hall that features a stop-chamfered bressumer above the inglenook fireplace. The loft is accessible via the external staircase, and there is a replaced hewn collared truss.