20, Castle Street

No 20 Castle Street is a building dating from the late 18th century to early 19th century, featuring a front that conceals an earlier timber-framed core. It is two storeys high and constructed of brick set on a projecting plinth. There is a string course at the first-floor level and a moulded wood cornice supported by pairs of cut brackets. The roof is covered with old tiles and sweeps out to the cornice.

The building has three windows on the upper floor, each four panes wide, with the centre window being three panes wide. Venetian shutters adorn the first floor. On the ground floor, there are two similar windows without shutters, alongside a central door that has six panels and an arched fanlight featuring a circular and curved pattern. The door is set within a panelled reveal and is framed by a doorcase with fluted Doric pilasters, a broken entablature, and an open pediment.

This building is part of a group that includes Nos 1 to 9 (consecutive) Lowndes Buildings, all located on the west side of Castle Street.