22, Castle Street

22 Castle Street is a late 18th-century town house that now serves as a museum office. It is constructed of Flemish bond brown brick and has a grey slate roof that runs parallel to the front. The building has three storeys with three bays, plus an attic. Access is via three stone steps leading to a porch with a door featuring five fielded panels on the east side. The first and second storeys each have three recessed 12-pane sash windows with thin painted-stone sills and wedge lintels. A narrow sill band is present on the second storey, and the third storey also has three recessed 12-pane sashes with similar detailing. A painted stone frieze and cornice are located beneath the rendered parapet. On the west side, there is one recessed sash window, now four-paned, with a painted stone sill and wedge lintel on each upper storey.

Inside, the staircase has been replaced and many original features have been removed. There is a small cornice in the hall and a cornice in the front room on the second storey. The rear room has a door with five fielded panels and two chamfered cross-beams. Most features on the third storey have been lost or covered.