L-shaped Barn Range at Plas-yn-Cefn

The L-shaped barn range at Plas-yn-Cefn is a large structure built of limestone rubble on rock foundations, topped with a slate roof featuring original kneelers and early 20th-century stepped gable parapets. The northeast side facing the yard has a primary entrance on the right, which includes a boarded door set in a pegged oak frame with an exposed timber lintel. There are two windows beside the entrance with modern multi-pane glazing, which were previously entrances. The east gable end has a blocked former entrance with an exposed timber lintel, now replaced by a modern window, and a boarded loading bay above that features a 20th-century multi-pane window. The northern corner displays an incised limestone quoin with a Welsh and Latin inscription and the date 1729. On the west side, there is an upper loading bay with a pegged surround and another boarded entrance on the right, also in its original frame, along with various enlarged openings at the rear.

To the southwest, there is a stretch of high rubble wall that includes ruined early 20th-century lean-to kennels on the east side. Inside, the barn retains original rough pegged collar and raking strut trusses, and an internal flight of stone steps leads down into the southwest section from the west entrance.