Gilwern

House, now officers' mess, dated 1903, in Renaissance Revival style. The building is constructed in red brick with red sandstone ashlar dressings and a plain tile roof featuring polychrome gable and ridge stacks. It is two storeys plus attics, arranged in an L-plan across three by five bays.

The principal elevations are characterised by ashlar quoins and round-topped gables with urn finials, with a plinth and first floor band running across the facades. Windows throughout are predominantly stone-mullioned leaded casements.

The entrance front features a central entrance bay with a pierced balustrade. A moulded elliptical arch frames an elliptical-arched half-glazed door with overlight and transomed sidelights. Above this is a sundial set in panels and flanked by relief figures of birds, with a three-light window positioned above. To the right stands a flush gable containing a three-light mullioned and transomed window, with two two-light windows above and a smaller two-light window in the gable head. A splayed corner to the right has a single window on each floor. The projecting gable to the left contains two cross-casements with two two-light windows above and a smaller two-light window in the gable.

The right return features a projecting gabled wing with a splayed corner containing a single window. A two-light cross-casement and two two-light windows with enriched heads are positioned across this elevation. Above these are two single windows flanked by pilasters and two-light windows, with a smaller two-light window flanked by pilasters under a gable supported by volutes. Within the return angle is an ashlar doorcase with strapwork pilasters, moulded cornice and pyramidal finials, the moulded elliptical arched doorway framing a panel above with crest and date. A T-plan stair window with 1/3/1 lights stands to the right. A plainer service wing extends further right, with an extruded corner and doorway in its return angle.

The garden front displays a projecting gabled wing with similar detailing, incorporating a cross-casement to the left and a five-light window to the right, both with enriched heads, plus a single window in the return angle. Above are a three-light window flanked by two-light windows, with a four-light window above again. The guest and service wing to the left has four mullioned windows on the lower floors and two gabled dormers with two-light windows. A hipped single-storey utility range extends beyond.

Internally, the central hall features a cross-beam on brackets with cornice, panelled dado, and a wooden fireplace with fluted columns. Panelled doors, two incorporating leaded glass, lead to a similarly detailed ante room via an elliptical arch. Doors and fireplaces throughout feature cornices and pulvinated friezes. The staircase and landing are fitted with square-turned balusters and square newels, with two-bay arcades to the landing. The stair window contains stained glass illustrations from Aesop.

Ground floor reception rooms have plaster-panelled and plain ceilings with cornices, and wooden fireplaces also with cornices. These rooms and the ante room feature windows with cusped heads and leaded lights, some incorporating stained glass. The dining room displays a patterned ceiling border and an elaborate fireplace with fluted columns and cornice, facing an elliptical-arched recess. An adjoining pantry contains panelled fitted cupboards.

First floor bedrooms and dressing rooms retain cornices and original fireplaces, two with overmantel mirrors. The larger rooms feature traceried leaded glass. Attic rooms have similar but smaller fireplaces. An open-well rear stair is fitted with panelled stick balusters.