Thames Block, Fort Blockhouse

Thames Block at Fort Blockhouse is a former officers' quarters, now functioning as an officers' mess. The core of the building was constructed between 1845 and 1847, with a memorial dining hall added after the First World War. Significant alterations took place around 1926 to 1929, when the range was extended to the south-west, a first floor was added across much of the building, and extensions were made to both the front and rear. Further additions were built to the rear during the Second World War, and the entrance porch was extended in the late 20th century. The rear mid-20th-century infill ranges and rear officers' accommodation block are of lesser interest.

The original construction used red brick laid in Flemish bond, while later additions employed dark-red stock brick in stretcher bond. Stone and concrete dressings feature throughout, and the roofs are covered in slate.

Layout and Development

The building's core comprises eight groin-vaulted casemates built between 1845 and 1847 at ground-floor level, with four on either side of a groin-vaulted passageway that serves as the north entrance to the artillery fort. During the 1926 to 1929 alterations, the main range was extended to the south-west, and a central entrance hall and staircase were inserted into one of the casemates. This work also introduced a second storey of officers' quarters. A single-storey extension was added to the western end of the front elevation, and three casemates were opened up internally to create a mess room. A meeting room sits adjacent to this. The four casemates at the east end of the range retain their dividing walls and original plan forms but now serve as offices. Several later additions extend to the rear of the main range, including the dining hall, kitchens, service rooms, and additional officers' quarters.

Exterior

The former casemates and officers' quarters occupy the north-west side of the bastioned artillery fort of Fort Blockhouse. The building runs north-east to south-west, with the south-east elevation forming the main façade facing the fort's interior. The main range is 15 bays long and three bays wide.

The ground floor of the front elevation, reading from left to right, comprises nine bays of sash windows in the single-storey extension added in the late 1920s beneath a flat roof, followed by a late 20th-century brick entrance porch, a groin-vaulted passageway through the range serving as the north entrance to the fort, and four blocked round-headed openings of the original casemates. The single-storey extension appears to have been built in two phases, evidenced by a straight joint in the brickwork separating the first three bays at the western end from the following six bays to the east. The first three bays feature a brick plinth beneath tripartite sashes and pivoted windows, each set under a segmental-headed arch with red brick voussoirs and concrete keystones. Above the windows runs a concrete string course, with a brick parapet and concrete coping above. The following six bays are similar in design, with a brick plinth, six-over-six sashes with red brick voussoirs and concrete keystones, and a brick parapet with concrete coping.

The adjacent late 20th-century entrance porch has a projecting entrance containing glazed steel double doors under a segmental-headed opening and a parapet matching the adjoining extension. Further east is the vaulted passageway, followed by the four casemates. The first casemate has a timber porch, and the first three all have doorways approached by brick and concrete steps with handrails. They feature six-panelled timber doors with transom lights flanked by six-over-six sash windows. The final casemate at the eastern end of the range has a tripartite segmental-headed window but no door opening.

The first floor of this elevation has 21 bays, largely comprising six-over-six sash windows with red brick voussoirs and concrete keystones. However, the window over the north entrance bay has paired four-over-four sashes flanked by brick pilasters containing narrow blocked loopholes for architectural effect. Beneath it sits a datestone inscribed with the initials V R (Victoria Regina) and the date 1847. The elevation is surmounted by a deep dentilled eaves cornice, a hipped slate-covered roof, and corbelled brick chimneys largely positioned off-centre towards the rear.

The south-west elevation adjoins the fort curtain wall and presents an irregular composition with one and two-storey additions extending from the rear of the main range. These have timber doors and segmental-headed sash windows.

The rear elevation, reading from left to right at ground-floor level, comprises a flat-roofed enclosed corridor, the gabled single-storey dining hall flanked by two gabled cross-wings to the main range, one and two-storey infill ranges added during the Second World War, and then a two-storey officers' accommodation block with a hipped slate-covered roof. The mid-20th-century infill ranges and officers' accommodation block are of lesser interest. The enclosed corridor at the east end of this elevation is nine bays long, largely containing eight-over-eight uPVC sash windows. It is entered via a half-glazed timber door approached by concrete steps with a steel handrail. There are blocked embrasures, probably for musketry, to the original casemates on this side of the main range.

Immediately to the right is the vaulted passageway to the fort, followed by a two-storey cross-range with a tall canted bay window lighting the staircase of the entrance hall. Further west is the dining hall, which is three bays long and three bays wide. The side elevations of the hall feature paired six-over-six sashes beneath top-hung windows flanked by brick pilasters and projecting chimney breasts. The gable end has two sashes flanked by pilasters and an oeil-de-boeuf set in the gable. Next to the dining hall is another gabled cross-range and several one and two-storey extensions constructed in dark-red brick with uPVC sash windows and uPVC doorways.

The officers' accommodation block at the far west is five bays long and three bays wide. It has six-over-six uPVC sashes, a plain eaves cornice, and a tall chimney, probably for an incinerator, attached to the east angle. The first floor of the main range has several sparsely separated uPVC six-over-six sash windows. The north-east elevation adjoins the North Bastion, upon which is an enclosed corridor linking Thames Block to Clyde Block (formerly Maidstone Block) via a first-floor bridge.

Interior

The entrance porch leads up some stairs and through glazed timber doors into the main entrance hall. The hall is covered by the groin-vault of the original casemate and is fitted out with wainscoting. On the left is a stone fireplace with a cast-iron grate, fireback, and hood, as well as a moulded mantelshelf and a wooden overmantel with a moulded cornice resting on two wooden Tuscan columns. Several wooden commemorative plaques are fitted to the walls, listing the commanders and captains of Fort Blockhouse and the commanders and surgeon captains of the Royal Haslar Hospital.

A double L-staircase with a wooden balustrade leads up to the officers' quarters on the first floor. Beneath the staircase landing is a doorway leading into the dining hall. The dining hall is open to the queen-post roof and is lit by a large leaded roof light and brass chandeliers. There is wooden panelling throughout and a wooden gallery with a balustrade at the west end supported on wooden Tuscan columns. The dining hall contains a series of fitted paintings of sailing vessels, after which buildings are named on the site, by the artist William Lionel Wyllie. These are considered to have been commissioned especially for the hall in memory of submariners who died during the First World War.

A wainscoted corridor leads off left from the main entrance hall. A mess room or lounge is situated at the front of the building leading off the corridor. It is covered by the groin-vaults of three original casemates, except for an additional bay under the 1920s extension. The mess room is wainscoted throughout and has brass chandeliers hanging from the ceiling. There is a stone fireplace with a Tudor arch and blind tracery. It has a metal fireback decorated with anchors, crosses, fleurs-de-lis, and other motifs.

Adjacent to the mess room under the westernmost three bays of the front extension is a meeting room. This has a wooden fireplace with fluted pilasters and an overmantel, and a coffered ceiling from which are hung brass chandeliers. The four casemates at the east end of the main range are accessed externally and now provide offices. These retain the original plan forms, being divided into individual casemates, as well as fireplaces. Leading off to the rear of the main range are the kitchens, bathrooms, other service rooms, and officers' accommodation, which are of lesser interest. The first floor of the main range contains the officers' bedrooms and bathrooms added in 1926 to 1929.