Numbers 20 and 21 and Attached Area Railings and Attached Rear Garden Wall

Numbers 20 and 21 Somerset Street are a pair of attached houses dating from around 1770. They are stucco and brick, with limestone dressings, limestone ashlar to the rear elevation, brick party wall stacks, and a pantile hipped double-pile roof. The houses have a double-depth plan and are in a mid-Georgian style. Each house is three storeys high, with a basement and attic, and is two windows wide. The ground floor is stuccoed, with brick above, and features pilasters to the cornice and parapet. Number 20 has a doorcase with consoles to an open pediment, a moulded keyed semicircular arch, a fanlight, and a six-panel door. Number 21 has a mid-19th century two-storey brick extension to the side. The ground floor of Number 20 incorporates an 8/8-pane sash window with flanking 6/6-pane sashes. Windows in Number 21's extension have flat surrounds and aprons, and upper-floor windows have cambered heads with five stepped voussoirs and 6/6-pane sashes. The extension has a three-window range, with plate-glass sashes divided by horizontal bars, sill bands, a first-floor lintel band, a frieze, and a cornice. The rear elevation of each house features a full-height canted bay, separated by a lead hopper and downpipe.

Inside Number 20, the hall is divided by fluted pilasters to a semicircular arch, and has wainscot and dado panelling. A central lateral dogleg staircase has a ramped rail, column-on-vase balusters, and column newels. The basement to the rear contains a built-in kitchen dresser. The house also features four-panelled shutters and six-panel doors. The attached features include front area railings to Number 21, wrought-iron railings with urn finials to the doorway of Number 20, and a brick garden wall to the rear.