Barn at Plas Gwyn

The barn at Plas Gwyn is a 7-bay threshing barn constructed of rubble masonry. Each bay features ground and loft ventilation slits. The central wide opposing doorways are topped with dressed stone voussoir heads, while a smaller doorway is located to the right. The roof is covered with slates arranged in diminishing courses, ending with a stone ridge. To the right of the main threshing door, there is a weighbridge consisting of a rectangular metal plate on the ground, with a small 4-paned light cut into it for viewing the weighing scales housed inside. The narrow doorway to the right is a later addition. The gable elevations also include ventilation slits, with three on the ground and first floors and two in the gable apex. The rear threshing door has been partially infilled with brick and now contains a 16-pane sash window.

Inside, the barn features rough hewn beams and collared trusses, with massive cross beams at the first floor level showing evidence of joists from a former loft floor. One of the beams is marked with carved initials and the date: W E J / 1732. The wide threshing doors are fitted with large tulip-headed hinges.