Little Llanthomas

Little Llanthomas is a sturdy 19th-century farmhouse. The main part of the building is constructed from thin, roughly-coursed rubble, with the ends and rear rendered. It features brick dressings around the windows, a blue slate roof, and red brick gable chimneys. There is a rear service wing and attached outbuildings that have red clay pantile roofs. The layout is L-shaped, consisting of a 1½-depth main range oriented roughly north-south and facing east, with a small service wing at the back of the north end. Additionally, there is a large lean-to, now used as a garage, attached to the north gable, and a single-storey outbuilding on the north side of the rear wing, which together create a service yard.

The east front of the main range is two storeys high and has three windows, appearing almost symmetrical. It features a plain doorway that is slightly offset to the right, with a board door. There are two rectangular 6-over-6 pane sash windows on the ground floor and three nearly square 8-over-4 pane sashes above, along with three small modern skylights in the roof. The south gable wall has a recently inserted tall window near the front corner. The rear wall includes a plain doorway in the centre, a two-light casement window to the right, and one three-light casement window on each floor to the left. The rear wing, which is 1½ storeys tall, has a two-light window near the junction with the main range, sheltered by a pitched canopy that suggests it was once a doorway. There is also an oblong window under the eaves and a gable chimney.

The south gable wall is very thick and incorporates the quoined right-hand jamb of a 17th-century fireplace at ground floor level, which has been reduced and remodelled, topped by a massive oak lintel. The room above features an unusually large chamber fireplace in the southeast corner, with stone jambs and a monolith lintel. A 19th-century fireplace is built into its right-hand side, while the left side has been recently broken through for an inserted window. This floor has two lateral beams, one of which is reused, with exposed joists between them that are alternately chamfered and square. The collar-truss roof consists of three and a quarter bays, with the quarter bay at the south end containing a doorway in the gable wall that appears to have been the top of a former spiral staircase in the southwest corner.