Building Number 47 (The Royal Marines Infirmary)

Naval ordnance storehouse with attached ancillary building, built around 1814 for the Board of Ordnance on the west side of Gunwharf Road, Portsmouth. Later converted to use as an infirmary by 1865 and now disused. The building is Grade II listed.

The main structure is constructed in patterned red brick with grey headers in Flemish bond, incorporating a section of tooled Portland stone plinth. Red brick segmental arches frame the openings. The ancillary building (number 92) is partly stuccoed. Both buildings are roofed with hipped Welsh slate. The style is late Georgian.

The main building (number 47) is rectangular in plan with a central stack and a ground-floor spine wall, with a single-depth block attached to one end. It rises two storeys with an attic storey. The front elevation is five bays wide and four deep, featuring small-pane windows set in reveals with stone sills. A 20th-century board door with a four-pane overlight is located in bay 4, while the ground-floor window in bay 5 has been bricked up. A plat band and string course run below the coped parapet. Two flat-roofed dormers project from the roof.

The rear elevation is similar in character, with several later alterations: the ground-floor left-hand window is blocked, the third window has been converted to a door, and a further door has been inserted between the left-hand windows. On the first floor, the central window is blinded. A battered ashlar plinth—probably part of an earlier perimeter wall—adjoins the building. Above this runs a segmental-arched two-light window, with grey headers in the upper section. The coping sweeps down toward the right.

The ancillary building attached to the rear of this wall has a hipped roof and stuccoed walls. It features a central 20th-century half-glazed door, a 16-pane sash window to the left, and an 8-pane sash to the right.

The right return elevation displays two wide segmental-arched recesses; the right-hand recess contains a 20th-century door and window, with two further inserted windows between the recesses. On the first floor, a recess with an inserted window appears on the right, another inserted window to its left, and an original window on the far left.

The left return has a door inserted in the right bay and a lowered window sill to its left. A 18th-century lead rainwater pipe with head survives here.

The interior ground floor is divided by brick walls with large-scantling cross-beams supported by slender cast-iron columns. Wide-board panelling lines the walls, and a cast-iron bolection-moulded Ordnance Board fire surround survives. A wide corner staircase with quarter landing and large scantling rails rises from this floor. The first floor is open, with the central stack rising to the roof. The roof structure comprises three braced king post trusses with queen posts and irregular braces, altered to allow passage and braced for end hips, similar in construction to Building No. 21.

The building was constructed to store armaments and ordnance for ships moored in ordinary at Portsmouth. It was probably built as part of the same programme as the Vulcan block, the main storehouse, sharing its characteristic brickwork as part of the New Gun Wharf extension to the yard dating to the 1770s. Similar brickwork appears at contemporary local Ordnance sites including Priddy's Hard. The building was adapted for use as an infirmary during the mid-19th century.

The building remains substantially unaltered and retains much original internal detail. It forms part of the significant historic dockyard complex at Portsmouth and stands as part of a good architectural group with the Vulcan block and former naval offices.