Ministry of Defence Building H7 at Tl 3756 0011

The Ministry of Defence Building H7, located at the Royal Gunpowder Factory, is a reel drying stove built in 1904. It features English bond yellow brick and hipped zinc-covered roofs, with a nearly flat roof over the porch. The building has a rectangular eight-bay plan, originally consisting of one room, and includes "truck porches" at each end. It is a single storey structure with eight-bay east and west elevations, which have red brick segmental arches above now-blocked windows. Mid-20th century double doors are present at both ends. The porches, which originally had tramways running to them, contain remnants of a "barrier board" designed to keep out grit and dust. Blocked round openings indicate where steam pipes entered the building. The interior was not inspected, but the roof was replaced after sustaining bomb damage around 1940. This building is associated with the manufacture of cordite, a process pioneered in Waltham, which became the main explosive used in the 1890s. The reel drying stove represents an advancement over an earlier model, as it was specifically designed to extract acetone after its use as a solvent in the manufacturing process.