17 Lower Castle Street

17 Lower Castle Street is part of a group of buildings at Nos. 17-21 Castle Street, constructed with roughcast render and painted finishes, topped with natural slate roofs, ridge tiles, and red brick stacks. The building has a double depth plan with entrances on the right side, except for No. 19. It stands three storeys tall with a basement and has a narrow single bay width.

The ground floor features an 8 over 8 pane sash window with a slightly cambered head, alongside a six-panel door, although No. 21 has an overlight above its door. The basement includes a small, mostly concealed window. The first floor window matches the ground floor, while the second floor has a 4 over 8 pane sash window. The roof is plain with a gable ridge stack that is shared with Nos. 19 and 21.

There is a replacement panelled door, and the rear elevation has not been inspected. The interior was also not inspected during the resurvey.