TB (Thomas Brown ?), 1809-10; earlier Assembly Rooms, 1783. Large 3-storey 13-bay classical exchange buildings, Assembly Rooms to N. Cream sandstone, polished ashlar basement, tooled ashlar above with polished dressings to front and N elevation, stugged ashlar to N; Assembly Rooms coursed and squared rubble with polished ashlar dressings to NW, coursed rubble to SE. Base course; rusticated ground floor with impost course; band course above ground floor; cill course at 1st floor; band cill course at 2nd floor; eaves cornice with blocking course; segmental-arched tripartite doorways with Doric columns and segmental-arched fanlights (No 37 with radial astragals); round-arched windows at ground floor flanking doorways set in recessed round-arched ashlar panels; smaller rectangular windows at 2nd floor.
NW (CONSTITUTION STREET) ELEVATION: 3 centre bays advanced at ground floor, doorway to centre with windows flanking; giant Ionic columns carrying blank frieze and pediment with clock; at 1st floor tripartite window at centre with segmental-arched ashlar fanlight and apron of blind balustrade, 2 single windows under ashlar panels with gilded inscription 'Exchange Buildings' flanking. 2 bays to left with secondary doorway to left and single windows to remaining bays. 2 bays to right of centre bays with single windows. Slightly advanced 3-bay end pavilions with advanced centre bay bearing tablet and doorway at ground floor; architraved, consoled and pedimented window at 1st floor. Single windows to outer bays, at 1st floor architraved, consoled and corniced.
NE (ASSEMBLY STREET) ELEVATION: single bay return of Constitution Street building detailed as pavilions with single windows. 5-bay 2-storey former Assembly Rooms (1783) to left; 3-bay hall with tall single windows adjoining Exchange Buildings; 2 slightly advanced quoined bays to left with plain doorway to right, rectangular fanlight with radial astragals, single window at 1st floor above; single windows to left bay.
SE (REAR) ELEVATION: single windows to earlier Assembly Rooms. Exchange buildings with projections and additions.
SW ELEVATION: 3-bay; band course above ground floor; single windows at ground floor, some with relieving arches. Gabled centre bay slightly advanced with skewline taken into corniced apex stack, at 1st floor tall tripartite window with broad panelled mullions and recessed ashlar aprons, round-arched fanlight (now blocked/relieving arch over (?); ashlar panel above. Single windows to outer bays
(blocked at 2nd floor).
Timber sash and case windows, mostly 12-pane or multi-pane glazing. Lead roof with metal flashings; 1 apex stack (see above), wallhead and transverse stacks.
INTERIOR: large ballroom (No 43) much altered; Adamesque plaster ceiling of earlier Assembly rooms now obscured by false ceiling.