Barn at Dyffryn Isaf

The barn at Dyffryn Isaf is a three-bay threshing barn with an added granary to the west, built from narrow rubble stone with larger quoins. The roof has a northern pitch covered in stone tiles and a southern pitch with concrete pantiles. The barn features a symmetrical design with a central passage leading to the threshing floor.

On the northern front, there are planked double doors set within a wooden frame, topped by a flat timber lintel and flanked by ventilation strips. A butt joint connects the barn to the granary. The granary's front includes a doorway leading to the loft, which is accessed by external stone steps and features a planked door with a small light in a wooden frame.

The southern side of the barn has double doors that match those on the front, but lacks ventilation strips. The rear of the granary features a doorway with a segmental head and voussoirs, positioned to the left, along with a boarded window for the loft that has a timber lintel and reveals partially in brick.

Adjoining the western end is a small lean-to, likely for a cart, which is open at the front with a timber fascia and masonry at the rear. There is another lean-to at the eastern end, also open at the front and topped with a corrugated roof. The apex of the eastern gable of the barn includes a ventilation strip.

Inside, the central bay has a flagstone floor and a roof supported by tie-beam trusses with collars. There is an opening to the granary with a square head.