55 King Street West, Helensburgh

51 King Street West in Helensburgh is a three-storey, near-symmetrical, L-plan local authority tenement block built in 1953, located at the corner of King Street West and James Street. The building is constructed from concrete blocks and features a base course and a cill course for the second-floor windows.

The elevation facing northeast at No. 51 has a block at the corner with a gabled entrance and stair bay set back on a diagonal line, connecting to two advanced piend-roofed blocks that are at right angles. The central entrance has a semi-circular-arched doorway, with a narrow recessed panel above that contains a small stair window on the first floor and a taller stair window above it, featuring a date stone between. The advanced bays on either side have windows on the ground, first, and second floors. There is a wallhead stack to the right of the gable. The return to the right onto Princes Street has a window on the ground and first floor to the left, and a tripartite window with timber mullions on the ground and first floor to the right. The second floor has three symmetrically arranged windows. There are also windows at the ground, first, and second floors on the return to the right in the re-entrant angle. The return to James Street mirrors the arrangement of the Princes Street elevation.

The elevation facing north at Nos. 53 and 55 on Princes Street consists of two near-symmetrical blocks with seven bays that are slightly set back and adjoin No. 51 on the left. There are six windows on the ground, first, and second floors in the center, including gabled dormerhead windows at the second bay on both the right and left. The gabled entrance and stair bays are detailed similarly to No. 51. The outer left has three windows on the ground, first, and second floors, including a gabled dormerhead window in the center. The outer right has three bays that are similarly detailed but feature a two-storey canted window crossing the bays to the right.

The elevation facing east at No. 53 adjoins No. 51 through a single-storey semi-circular-headed archway. This symmetrical seven-bay block is detailed like the northern elevation, with canted windows crossing the outer bays on the first floor. The south return has a wallhead stack in the center, with windows at the ground, first, and second floors on both the outer right and left.

The building primarily features 12-pane sash and case windows, a green slate roof with red ridge tiles, and tall coped stacks.