East Crystallising House (Building 11) At Former Marsh Gunpowder Works, Workshop Area

The East Crystallising House, also known as Building 11, is a crystallising house at the former Marsh Gunpowder Works in Faversham, built in 1789. This single-storey structure features a long, narrow plan and is timber framed, clad with weatherboard, and topped with a hipped roof made of corrugated iron.

The exterior is notable for its 12 bays, supported by strutted timber posts, with the northeast side now open, showing evidence of former louvres. The ends and rear of the building are covered with louvred openings, and there is a central doorway.

Inside, the building has strutted king post ties, corner ties, and matchboard lining on the roof. Historically, this crystallising house was used to crystallise saltpetre from a solution treated in the nearby refining house. It was designed to allow the solution to cool in racks of vats, which explains its open structure.

The Marsh works were part of the Royal Gunpowder Factory established in 1786 to improve safety after an explosion in Faversham. Under William Congreve, these works played a significant role in enhancing British gunpowder production during the Napoleonic Wars. The saltpetre refinery was built as part of Congreve's efforts to improve gunpowder ingredients. The site was privatised after the war and closed in the 1920s.

The East Crystallising House is the best-preserved building on this historically significant site and serves as an impressive example of late 18th-century industrial architecture, reflecting the close relationship between the structure and the production process. It is part of a coherent group of late 18th to early 19th-century industrial buildings for refining saltpetre, recognized as the best preserved of its kind in the UK, comparable to examples found in France and Sweden.