NW.Range & attached Walls to Walled Garden at Trenewydd

The house at Trenewydd dates to the earlier 19th century, built on an earlier core. It is constructed of rubble stone with slate roofs and stone end stacks. The main, two-storey range has three windows and features renewed 12-pane sash windows with painted brick heads and slate sills. The central window has a raised sill and a tripartite sash with a small, hornless 4-8-4 pane arrangement. Glazed doors are situated below, beneath an added gabled porch with a front Gothic traceried window and painted brick head. A rear outshut and two later rear wings are present, along with a hipped centre stair tower with a pointed traceried stair light.

A lower service range to the west features a large end stack, two large pairs of sashes above, a ground floor Gothic window, and a central glazed door. Lean-tos extend from the west end and the rear.

Attached to the northwest is a later 19th-century two-storey outbuilding with a lean-to coach-house in the angle. The coach-house has a north-end arched entry and half-hipped gable, while the main part has a blocked entry similar to the coach-house, with a small sash window above. A small sash window with a blank arch above is situated on the north end wall, alongside a stone end stack. Outside stone stairs are at the south end, and 20th-century windows are on the west side.

A walled garden is attached to the northeast and is enclosed by rubble stone walls.

The entrance hall and stair foot feature attractive plasterwork, including inset acanthus leaves on flat brackets, an elliptical arch panelled with brackets supporting each side, and a small rectangular moulded ceiling beyond the foot of the stair. The northeast room has a moulded ceiling border in a Regency style, with long panels and rosettes to the centres. Six-panel doors are throughout the property. The service range includes a large timber-lintel fireplace. A lean-to behind contains an ancient oak table-top resting on stone piers with a cobbled floor; the table is said to date from the 16th century. The northwest rear wing was formerly a dairy. The staircase has a thin ramped rail, stick balusters, and a thin turned newel. The stair ceiling features a thin moulded cornice, with shallow canted sides to a rectangular centre panel containing a cruciform and foliated plaster motif. There's an elliptical arch at the stair head. Upper rooms have six-panel doors with Regency surrounds. The northwest and centre rooms have moulded ceiling surrounds with rosettes in the corners, while the northeast room has a more elaborate oak-trail surround and a small acanthus cornice. Narrow fireplaces and iron grates are also present.