90 Constitution Street, 88, Edinburgh

90 Constitution Street is an early 19th-century, three-storey and attic tenement building featuring seven bays, a pend, and shops on the ground floor. At the rear, there is a three-storey former wireworks (No 86). The building is constructed from cream sandstone with a stugged ashlar front and polished dressings, while the rear is made of coursed and squared rubble. The wireworks has a coursed and squared rubble front and random rubble to the rear and sides. The ground floor is rusticated, with a band course above it, and a band cill course at the first floor. The first-floor windows are architraved and corniced, and there is an eaves cornice and blocking course at the top.

On the front elevation, there is a segmental-arched pend in a slightly recessed bay to the outer right, featuring timber beams and ornate cast-iron gates. The remaining bays include a central common stair doorway with a panelled door and a blocked rectangular fanlight. The shopfronts have central doorways flanked by rounded and moulded reveals, topped with a heavy dentilled cornice. The first and second floors have regular fenestration, and there are three later mansard dormers added in 1897. The building also has vaulted cellars.

The rear elevation features windows and a short, broad wallhead stack at the center. The wireworks is a three-storey, rectangular-plan structure with a piend roof and irregular openings that have been much altered. There is a raggle of forestair to the left and a large opening leading to the workshop on the right, along with vaulted cellars.

The building has timber sash and case windows, with plate glass glazing on the front and some 12-pane windows at the rear and in the wireworks. The roof is covered with black slate and lead flashings, featuring apex stacks on the side elevations and one transverse stack.

Inside, the shop at No 90 has ornate cornices, while No 88 features a stone flagged entrance, a stone stair, and plain cast-iron balusters.