St Joseph's R.C. Church, Lomond Street, Helensburgh

St Joseph's Roman Catholic Church, located on Lomond Street in Helensburgh, was designed by C J Menart and completed in 1911. This cruciform-plan church is built in a late Gothic style and is situated on a corner site, featuring a canted apse to the west and projecting stair towers flanking the entrance on the east elevation. The exterior is constructed from squared and coursed bull-faced red sandstone with ashlar dressings. The windows are chamfered pointed arches with stylised bar tracery, with two-light windows for the nave and choir and four-light windows for the transepts.

The east elevation, facing Lomond Street, has a gabled design with an ashlar panel at the center that includes paired segmental-arched doorways topped by a large rose window. Each doorway has stop-chamfered reveals, hoodmoulds, carved lavel-stops, and two-leaf panelled doors. The ashlar frieze features foilate carving flanked by angels in shallow relief, with a statue of St Joseph in a decorated canopied niche at the center. The large rose window above showcases stylised bar tracery. There are lower projecting stair blocks on both the right and left sides.

The south elevation features a gabled stair block on the outer right, which has a narrow window at both the ground and first floors set within an ogeed arch ashlar panel. A conical cap is present on a bollard at the southeast angle. There is a single-storey L-plan passage aisle with a lean-to roof situated between the transept and the stair block. A canted doorway is set diagonally in the re-entrant angle, breaking the eaves, and has two-leaf boarded doors in an ogeed polished ashlar panel. Above, there are four windows to the nave.

The advanced gabled transept on the left side includes a four-light window, while a single-storey lean-to block in the re-entrant angle to the left has two two-light windows above the chancel.

The west elevation features a canted apse. The north elevation mirrors the south elevation and includes a piended single-storey vestry at the northwest angle, which has a boarded door and two narrow windows on its north face. The church has square lead-pane glazing, a grey-green slate roof with red ridge tiles, and ashlar coping on the skews and gablet skewputts.

Inside, the church features a four-bay arcaded nave and passage aisles, with a timber-boarded vaulted roof and a gallery to the west.

The gatepiers and gates consist of octagonal ashlar gatepiers topped with corniced moulded caps, and stylised wrought-iron gates.