Leith Nautical College, Macdonald House, 104, 106 Commercial Street, Edinburgh

The Leith Nautical College, now Macdonald House, is a substantial building located at 104-106 Commercial Street, Edinburgh. It was originally designed by William C Laidlaw and constructed in 1903, with subsequent extensions in 1926, 1931, and the 1960s. The building was converted to offices in 1981 by Gordon and Latimer.

The building is an example of English Baroque architecture, and is symmetrical in design, standing two storeys and an attic with a three-bay main section, and a single-bay addition to the east. The exterior is faced with cream-coloured ashlar sandstone, with squared snecked and bull-faced stone at the rear.

The south elevation, facing Commercial Street, features a base course, cornicing to the ground floor, a moulded cill course to the first floor, and a mutuled cornice with a blocking course at the top. Long and short quoins emphasise the corners. A projecting doorpiece contains a pair of panelled doors with a semi-circular, leaded fanlight, framed by engaged Ionic columns on pedestals, supporting a broken pediment with a cartouche inscribed "MACDONALD HOUSE". Three tall windows flank the doorpiece at ground level. Venetian windows are positioned in the first-floor bays, with brackets centrally positioned beneath them, and plaques set between the bays. Corniced box dormers are situated in the attic, with a bipartite central window and tripartite outer windows. A single-bay extension to the right mirrors the rest of the facade, although it lacks quoins. It also has a full ashlar attic storey with four round-headed windows grouped centrally, and a corniced tablet above the parapet bearing the inscription "LEITH NAUTICAL COLLEGE ENGINEERING DEPARTMENT ERECTED 1926." A modern two-storey glazed brick extension is present to the right. Adjoining the building to the left is a cooperage.

The north elevation features a two-storey and attic three-bay design; the centre and left bays are partially obscured by a modern breeze block addition at ground level. A stair window occupies the central bay of the north face, with a raised wallhead forming a square watchtower, which is topped with a glazed, ogee-roofed timber cupola behind a central stack. The right bay includes bipartite and single windows on both floors, while the left bay features a tripartite window on the first floor. Corniced tripartite box dormers abut the watchtower.

Original timber windows remain, featuring plate glass in the lower panels and multi-pane glazing above. The roof is piend, with a platform and railings around the viewing platform, covered with grey slates. A corniced ashlar stack is located on the west side, and original cast-iron rainwater goods are still in place.

The interior includes a plaster corniced and consoled vestibule. Classrooms were later partitioned, and stained glass, cornices, and figurines were added to the stair around 1978-9.

Dwarf saddleback-coped ashlar walls with original decorative wrought-iron railings flank the doorpiece.