18 Blythswood Square, Glasgow

20 Blythswood Square in Glasgow is a classical terrace block built around 1823, featuring three stories and a basement. The building has 21 bays arranged in groups of three, with the outer bays raised and projecting forward to create pavilions. The ground floor is finished in polished ashlar with channeling, and there are voussoirs above the openings. The elevation facing Douglas Street is painted.

The building includes distyle Ionic porticos, which have been altered at No 20, and an Ionic pilastered, pedimented doorpiece at No 108 Douglas Street. All entrances at Blythswood Square are accessed via a stone stair that oversails the basement area. There is a basement band course and a cill band at the first floor. The windows are primarily sash and case, featuring 12 or 4-pane glazing. The ground floor openings are set in recessed arches, with windows that have moulded cills and aprons. The first-floor windows are architraved and corniced, with console detailing in the end sections, while the second-floor windows have plain architraves. The building is topped with an eaves cornice and a blocking course, and there are cast-iron railings.

To the rear, there is a three-bay return to Blythswood Street, which features a rising basement due to the slope of the land and repeats the detailing of the main elevation. There is also an eight-bay return to Douglas Street, with the second bay from the south being blind and two bays having splayed cornices. Wallhead stacks are present. Inside, some cast-iron street balusters remain.