South Gate House

South Gate House is a gatehouse and office building, dating to the mid-1820s. It was likely designed by George Ledwell Taylor, the architect for the Navy Board, and Sir John Rennie, the engineer, as part of the rebuilding of Sheerness Naval Dockyard. The building is constructed of yellow stock brick with rubbed brick heads, a granite plinth, limestone dressings, brick ridge and lateral stacks, and a slate hipped roof, and is in a late Georgian style.

The building has a two-room, single-depth plan with a central transverse stair and an L-shaped south annexe. From the exterior, it presents two storeys with a four-window range to the north end and a single-story, four-window range to the south. A wide granite band runs beneath the ground-floor windows, with a first-floor cill band, cornice, and parapet above. The ground floor features round-arched windows recessed in matching details, while the first floor has flat-headed windows with six-over-six-pane sashes, and blind windows to the east elevation.

The north entrance end is rendered to the ground floor with three round-arched recesses. The easternmost recess contains a round-arched doorway with a fanlight, featuring a central round pane, and a six-panel door with glazed top lights. A six-over-six-pane sash window sits above the doorway, and there are two blind windows. A round-arched doorway is present on the west side, one bay from the south. The lower south section, possibly a former guard house, includes a one-bay forward wing with a tall lateral stack, an arcade of round-arched former entrances linked by an impost band, and a parapet. This wing has an inserted late 19th-century doorway with a fanlight, flanking late 19th-century tripartite sashes with margin panes, and a remaining original six-over-six-pane round-headed sash window.

Inside, the building retains a dogleg stair from the west entrance, featuring iron stick balusters and a curtail with a fluted newel. Other interior details include six-panel doors, plain cornices, and stone fire surrounds.

Originally, South Gate House housed the police station and surgery, serving as one of the entrance lodges to Sheerness Naval Dockyard. It connects to the east boundary wall and was formerly linked to the north lodge (The Gatehouse, Main Gate) opposite by a granite colonnade. It occupies a little-altered southeastern corner of Rennie’s model layout, which included offices, the chapel, officers' accommodation, and part of a unique planned early 19th-century dockyard.