Cefn-ydfa farmhouse and adjoining ruins.

The present house is of stone, rendered, with a slate roof. Two storeys, 4 bays. Wide oak front door set near the centre, formerly the mid C17 service hall. Four bays of irregularly placed mid C20 small-paned oak casement windows to both floors under timber lintels. A kitchen outshut is attached to the rear, late C19 or C20. Gable stacks, and a primary off-centre stack. The C18 house developed to the E now survives only as as low walls, terminating in a substantial partly-walled bay of the former E end, displaying internal fireplace and openings. It formerly was of 2 storeys with attics, five bays, and lit by 5 gabled dormers.

The present house has large widely spaced chamfered cross beams, without end stops. The fireplace to the secondary end bay has been altered, and includes two side ovens from the period when it served as a kitchen. Segmental rubble arch over. This bay was opened into the main central bay c.1974. This has a stone axial fireplace, with the stair on its north side, and chamfered ceiling beams and subsidiary joists with pyramid stops, not now visible. The room was originally sub-divided to form an inner room. Recently introduced C19 Carrara marble fireplace.