Fort Halstead: Building F11

Fort Halstead, located on a prominent hilltop in the North Downs, includes the late 19th-century Mobilisation Centre and various buildings related to the research facility. Building F11, known as the Experimental Filling Shed, is a two-storey structure with a concrete frame encased in buff brick laid in English bond. It has an L-shaped plan and a sloping concrete roof. The main elevation faces east and features an external metal stair leading to a first-floor covered walkway. There are two pairs of double doors on the ground floor and two pedestrian doors on the first floor, all with glazed lights. The windows consist of metal-framed casements. The rear (west) wall has four external doors, two on the ground floor and two on the upper floor, which are now blocked, likely serving as emergency exits, along with additional metal-framed casements. The south elevation has paired replaced casements on both floors, while the north elevation is blind. Overhead cable gantries extend north from the building. The interior, not inspected, contains brick-built vertical filling bays for assembling a 9-foot rocket, as noted in an English Heritage Research Department report.