Engine House Immediately South-East of Black Mill

The engine house, built around 1840, is located immediately south-east of Black Mill. It is constructed of red brick laid in Flemish bond and features a hipped slate roof. The building is a single storey with a square plan, including small outshuts to the north and west, both covered with corrugated iron roofs.

On the north elevation, there is a gabled outshut with double timber doors to the left of a doorway, which is set under a gauged skewback arch. The west elevation has vertical weatherboarding on the outshut, which protects the differential gearing of the turbine. There is a ghostly outline of a very large scoopwheel against the main wall, which was driven by the original steam engine. The south elevation features a 6/6 unhorned sash window under a gauged skewback arch to the left, along with an inserted plank door to the right. The east elevation has two 6/6 unhorned sashes under gauged skewback arches to the left and a blocked doorway to the right.

Inside, the engine house contains two rooms of unequal size with a boarded ceiling. The west room houses a diesel engine from around 1930, made by Ruston of Lincoln (Hornsby & Ruston), with a flywheel set within an intact protective timber cage. The east room contains two cylindrical fuel tanks and an iron water tank located in the roof space, supported by paired joists.