Royal Arsenal Building 20

Building 20 of the Royal Arsenal, located on Plumstead Road, is a Grade II listed chemistry laboratory that was completed in 1864 for Sir Frederick Augustus Abel, the War Department Chemist. The building was extended to the east and south in 1885, 1903, and 1913. It is constructed of yellow brick with red brick dressings and features ridge stacks and a slate roof. The structure has a double-depth plan and is two storeys high with an 11-window range.

The symmetrical front includes a plinth, moulded impost bands, a first-floor cill band, and a brick eaves cornice. The central five-bay range is recessed and articulated by pilasters with moulded capitals. A round-arched doorway at the center has a fanlight and a door with eight raised diamond panels, alongside rubbed brick keyed round-arched sashes with margin panes. The side elevations mirror this design with three windows each, and the rear features three-by-three bay blocks, one of which has a glazed clerestorey.

Inside, the building contains a central dogleg stair with ornate cast-iron balusters and a twisted newel, as well as curtail and moulded railings, an axial passage, and panelled doors. The left-hand room is open to the roof, showcasing cast-iron elliptical arches with open spandrels on moulded corbels, which span the room and feature similar arches at the hips. A timber balcony encircles the room on foliate cast-iron brackets with railings that match those of the stair.

Historically, this was the first custom-built laboratory in the Arsenal, designed to allow fumes to disperse from the lab benches in the open left-hand room. The east wing housed the early photographic section of the War Department. The building once featured iron balconies at both ends and is recognized as an early example of a purpose-built chemical laboratory, highlighting the importance of the chemist in advancing research and development in Europe after the 1850s.