21-27 Montague Street, Rothesay, Bute

21-27 Montague Street is a three-storey tenement building dated 1832, located on a corner site in Rothesay, Bute. The building features classical detailing and includes shops on the ground floor. The northern elevation faces Guildford Square and has seven bays, while the western elevation on High Street has three bays, with a full-height slightly recessed bowed single bay at the corner.

The northern elevation is finished in painted render, with a raised base course, projecting eaves, and architraved surrounds around the first-floor windows, which have projecting cills. The western elevation is constructed from coursed red rubble sandstone, featuring droved quoins and droved long and short red sandstone dressings around the openings, also with projecting cills.

On the northern elevation, there is a pend entry at No. 25, offset to the right of centre, with two shops to the left and a single shop to the right that showcases arcaded columnar cast iron detailing with decorative pendentives. The penultimate bay on the outer left has bipartite windows on the first and second floors, while the penultimate bay on the outer right contains blind windows on both floors. The remaining bays are regularly fenestrated. The outer right features a slightly recessed full-height bow with single windows on all floors.

The western elevation has a shop at ground level and is regularly fenestrated on the first and second floors, with a blind window on the second floor in the outer left bay.

The building predominantly has later glazing, with some 12-pane timber sash and case windows. The roof is covered with graded grey slate, and there are replacement rainwater goods. The northern elevation has a coped ridge stack with various circular cans, an apex stack to the east, and a corniced wallhead stack to the west, which features consoled detailing at the base and a central panel inscribed "Built in 1832 Captain James........", along with circular cans.