Range of Outbuildings on S side of farmyard at Castell-du

The range of outbuildings on the south side of the farmyard at Castell-du is constructed from whitewashed rubble stone and features a slate roof. The upper end of the building is obscured by an attached range that runs northeast, which is likely an addition and includes a loading door at the west end.

Facing the main yard and running downhill, the first structure is a heavy-horse stable, which has a window, a door, and another window, all under timber lintels. Next is a small cow-shed that also features a door and a window with timber lintels. Following this is a large arched cart-entry, made with stone voussoirs, and equipped with inward-opening double doors. To the left of this entry is a window with stone voussoirs and a door with a timber lintel leading to a loose-box. The east end wall has a lean-to duck-shed with a door and a flight hole above it, while dove-holes are present in the main east gable. The northeast corner of the building has a curved angle.

Inside the two-bay cow-shed, there is one collar truss with scarfed feet, and it contains two stalls. The left end features a three-bay tie-beam and collar roof over the cart-entry and loose-box. The heavy horse stable accommodates seven stalls.