Belper North Mill - Construction

Construction

The iron-framed mill is 127 feet (39 m) long by 31 feet (9.4 m) wide, 63 feet (19 m) high. It had two 41.5 feet (12.6 m) by 34 feet (10 m) wings.

Cotton mills were prone to fire as cotton dust ignites easily and the resulting fire burns through ceiling and floor timbers. This had happened to earlier mill. In an attempt to prevent this happening experiments were made to construct a fireproof mill. The wooden beams supporting the floor timbers were replaced with beams of cast iron, (steel was not available till after 1860) and between them were low vaults made of brick with a 9 feet (2.7 m) span. Above this rubble was used to level the floor which was made of brick. The floor arches over the wheel pit were of a hollow clay construction.

The beams were cast in a "turtle back profile" to give the required strength, at minimum weight. They were supported by cast iron columns, erected on top of each other. The lateral thrust of the brick arches was resisted by concealed wrought iron ties between the column tops. The building was 15 bays wide, and the wings six bays wide.

The mill is one of the first iron framed buildings. The technology is the precursor of the steel frames used in high rise buildings. The roof was made of slate and had internal gutters.