Rockhill Castle, Ardencraig Road, Craigmore, Bute

Rockhill Castle is a large villa, mostly dating from 1883 with various asymmetrical additions, situated prominently on a sloping site in Craigmore. The building comprises a 2- and 3-storey main block with basement and attic, a single-storey entrance range to the roadside dated 1891, and several later extensions. It is constructed predominantly of cream sandstone rubble, partly rendered, coursed and whitewashed, with a ladder-pinned sandstone ashlar engaged octagonal tower to the south-east, a squared and snecked sandstone bow to the north-east, and polished sandstone dressings throughout. A raised base course, architraved cill course, and corniced eaves emphasise the classical detailing of the villa. The roadside entrance range is finished with a polished sandstone blocking course.

The western entrance elevation presents a 2-storey, 4-bay core block with an advanced single-storey store to the left, linked by a low coped wall to a 4-bay entrance range offset to the right of centre. The entrance itself features a 2-leaf timber panelled door surrounded by an architraved surround with stepped hoodmould, dentil detailing beneath a frieze, an advanced blocking course, and a pediment bearing the embossed inscription "Rockhill Castle, 1891" with flanking consoles and an anthemion-shaped finial. Tripartite windows occupy the bays to left and right of the entrance, with a single window in a recessed bay to the outer right. The store has a boarded timber door offset to the left of centre. The core block displays a bipartite window at ground level in the outer left bay with a 3-light pedimented oriel breaking the eaves above, a single window at ground in the right bay with a single gabled window breaking the eaves above, and another single gabled window breaking the eaves offset to the right of centre.

The western rear elevation is the most ornate. A 2-storey, three-quarter-engaged octagonal tower projects from the outer left bay with a balustraded parapet, surrounded at ground level by a decorative cast-iron verandah supported on stylised cast-iron columns descending to the basement, with intricate spandrels. An arcaded arbour is recessed below the tower. The central bays contain a later quadripartite conservatory at ground level. A single window is set in a later flat-roofed tower offset to the left of centre, and a gabled single window appears at 1st floor level offset to the right. A full-height 3-light canted bay faces south in the re-entrant angle, and a 5-light bow is advanced to the outer right facing west, centred beneath a pediment above 1st floor openings.

The southern side elevation features a single-storey, single-bay entrance range to the outer left, with a single window to the right. The 2-storey, 2-bay core block at the centre comprises a 3-light bow recessed at ground level to the left, a 3-light pedimented canted window above with decorative cast-iron finial, a single window at ground offset to the right of centre, and a small single gabled window breaking the eaves above. A 2-storey engaged octagonal tower projects at the outer right.

Windows throughout are predominantly 2-pane timber glazing with upper panels stained and etched. The roof is grey slate, piended at the centre, with coped wallhead stacks to the west and north, corniced stacks at the rear, and various circular cans.

The interior is enriched with extensive timber panelling, arcaded passages, intricate plaster cornices and ceiling roses, a timber balustraded stair, and decorative leaded and stained glass panels. Some original fireplaces remain. The arcaded games room is set in the single-storey rear bow and features fluted balustraded columns, intricate Corinthian capitals, studded decoration, and raised keystones.

Terrace walls at the rear comprise coped random rubble sandstone with regularly-disposed square-plan corniced ashlar piers. The boundary walls to the north and west are of coped random rubble sandstone with corniced ashlar piers featuring stylised consoled detailing flanking the entrance block.