Robert Adam, 1791-9, completed posthumously. David Hamilton extensions at rear 1838, interior recast by James Sellar in 1887-8 partially or totally refaced by John Keppie 1927; 1916 John Keppie redecorated the saloon. 1955 extensive alterations and new trades' hall ceiling by Walter Underwood. Classical building. 2-storey and full attic, symmetrical 7-bay elevation, alternately recessed and advanced. Polished ashlar, rusticated ground floor with bold voussoirs to openings. Various alterations to ground floor openings, including reduction to size of main door and insertion of stained timber windows with panelled aprons. Tall 1st floor with pairs of Ionic columns supporting central pediment; 3 Adam-type Venetian windows in advanced bays (with altered glazing); console pedimented windows in recessed bays. Raised attic over 5 inner bays, central parapet with paterae, supporting Royal Arms. Set back centrally, domed drum with louvred aedicules and leaded cupola. Outer bays raised from single storey by Sellars (1887). 2 bronze panels above pedimented windows, of gryphon-flanked vases.
Small-pane glazing to main, hopper windows, plate-glass sash case to outer bays and attic.
INTERIOR: reconstructed 1887-8 by Sellars. Grand stair rises in 2 flights to 1st floor with fluted newels supporting bronze lamp standards, stained glass by Sellars.
BANQUETING HALL: remodelled by Sellars with Adam-style ceiling, replaced 1956 with African timber ceiling, silk frieze depicting Trades at work, 1902-03.
SALOON: Spanish mahogany panelled with plaster panelled ceiling. Glass by Guthrie and Wells 1897. Adamesque marble chimneypiece.
Main entrance: decorative mosaic floor inscribed "Trades House".
Part of ground floor absorbed into adjoining bank at No 99 Glassford Street.