Main Tannery Building at Isinglass Factory

The Main Tannery Building at Isinglass Factory is a complex of buildings dating from 1847/8 to the mid-19th century, located in Coggeshall, Essex. It comprises parts of a tannery, gelatine and isinglass works, including a mill, warehouse, and beam house. The buildings are constructed of brick with slate roofs and feature sash and casement windows.

The mill building, to the northwest, is a three-storey structure with ten bays, incorporating pivoting sash windows and an oculus to the gable end. It has an internal angled queen strut roof with five tiers of purlins. Notably, pieces of wood with shallow slots cut into them are nailed to the tie beams; these held poles used to suspend strips of isinglass for drying. An original wooden staircase is present.

The northeastern building is two storeys high, with five windows on the south elevation and the ground floor of the north elevation, all with chamfered flat-arched heads. Internally, it features a queenpost roof and purlins with horizontal boarding, alongside cast columns on the ground floor. An original staircase is retained. This building previously housed a single-storey horizontal steam engine (removed) and may have begun as a warehouse or storehouse. Projections to the north and east extend from this building, the purpose of which are currently undetermined.

A single-storey building to the southeast, in existence by 1853, is believed to have been part of the original tannery complex, containing internal tanning pits. The roof has been altered. To the southwest is a single-storey building, believed to be the original gelatine/isinglass works of 1847/8, with a roof altered after 1875, later known as the weighing room and beam house. A one-storey section was later inserted between the beam house and the western tannery building, dating between 1853 and 1875, initially used for skin preparation for gelatine manufacture, later becoming an isinglass production facility. A further single-storey range connects the southwestern and northwestern parts of the complex, existing by 1875, and used for storing and sorting dried swim bladders prior to processing.