Arllen-fawr (formerly Garthgelynen-fawr)

The front of Arllen-fawr farmhouse is a two-storey, four-window elevation facing south (away from the road), and is of white-painted slate with a slate roof slightly sprocketted over a bracketted eaves. The three window part of the range to the left constitutes a symmetrical composition with door at centre and chimneys at each end. Part of a plat-band survives to the right of the door. Four-pane C19 horned-sash windows in all positions plus the additional bay to the right. Semi-glazed panelled front door in a panelled door casing, with plain pilasters carrying a projecting entablature on carved volute brackets. The doorway entablature has two elements with large dentils and an ogee. Sides and rear of unpainted and uncoursed slate; low pitch rear slate roof.

Entrance room with late C18 relocated staircase to right, with thin turned balusters to stairs and landing, turned newels, cut string with bracketted and moulded stair ends. Much exposed timber framing (some decorative, some utilitarian) in partitions and ceilings. Room to left appears to have been the original parlour, and has main beams dividing it into four, with large chamfers, and flat-laid ceiling joists simply moulded at edges. To rear is much exposed lozenge-braced timber framing visible in the front and rear rooms. Eared C18 timber fireplace surround in front bedroom at left, with plain frieze and beaded moulding at top.