Exterior
The hospital is built of red brick with yellow brick banding, Welsh slate roofs; the entrance block main elevation has ground floor and dressings of Bath stone. Developed form of 'broad arrow' or echelon plan widely used for large mental hospitals from later C19. Spine of administration and service blocks has, to each side, five two-storey ward blocks (roughly L-shaped) stepped back in echelon, and connected by curved corridor to rear, and cross corridors. Convex (south) side faces out to give sun and light to ward blocks; concave corridor thus encloses service blocks with entrance block facing north.
Entrance block in Wrenaissance style. Two storeys, three bays with advanced gabled central bay with open porch below. Slate roof with weathered red brick end chimneys, and two smaller chimneys to ridge. First floor in brick with deep eaves band course (dentil cornice) and dressings in Bath stone; ground floor in horizontally chanelled Bath stone. The windows are horned sashes with small panes to upper sash and single large pane below. Single first floor window to each outer bay has architrave with keystone and rusticated surround. Two ground floor windows to each outer bay. Advanced central bay has a broken pediment, end paired Ionic pilasters, large round-headed first floor window with keystone and rusticated surround, on ground floor open segmental arch to porch; returns have two windows to first floor (rusticated surrounds) with ground floor arches similar to front. Gable ends treated as pediments with projecting central stack. To each side of two-storey section, attached single storey pavilions, hipped roofs, banded Bath stone, semi-hexagonal bays to front, two windows to returns. Rear of entrance block in red brick and connects with body of hospital via corridor flanked by one- and two-storey office blocks.
To east (left) of entrance, yard formed by L-shaped works and laundry blocks (mortuary block to north) has boiler houses (with prominent ridge ventilators) and 2-storey attached range. To rear of boiler houses is combined water tower and chimney. Top stage consists of copper dome with small lantern over open loggia (3 bays to each side), brick pillars with stone capitals and cornice. Freestone cornice and bandcourse, roundels, yellow brick bands. Attached chimney follows water tower up to cornice then becomes cylindrical chimney in brick.
To west (right) of entrance, area between corridors has attached service buildings in matching materials.
Disposed to either side of entrance are ten roughly L-shaped 2-storey ward blocks in red brick with yellow brick banding; red brick chimneys, slate roofs, small-pane horned sash glazing. Blocks connected to each other and/or to rear corridor to enclose small courtyards; to rear, each ward block has attached two-storey sanitary block and ventilation cupola in red brick with wooden louvres surmounted by small dome and pinnacle. Ward blocks are disposed almost symmetrically, and are numbered 1 to 5 East and West respectively. Wards 1 (East and West) have two-storey splayed bays near inner angles. Ward 2 (West) has bay in same position, but block 2 (East) has bay near centre of elevation. Wards 3 and 4 to each side have polygonal corner bays. Wards 5 to each side have two splayed bays to outer corners.
Some ward blocks have, on south facing walls, modern single-storey shallow extensions in yellow brick with corrugated roofing materials; some 2-storey extensions in red brick.
Between Wards 1 (East and West), is 2-storey staff house connected by corridor to body of hospital, six windows with recessed central bay, and ground floor splayed bay-windows to outer bays. To rear of house, 2-storey physiotherapy and pharmacy departments. Behind these, other blocks include main recreation hall, largely obscured by adjacent buildings but with prominent louvre, and kitchens. A network of corridors forms courtyards with buildings attached to corridors for office, medical, and service uses.