A group of buildings close to the north-east end of No 6 mill, Diffwys Quarry (NPRN 415671), built from slate blocks most of which display sawn surfaces. The main portion consists of two large, interconnected rooms, formerly under a pitched roof, with fireplaces sharing a slate-built chimney built into the dividing wall. Entry to the building was by doorways in the south gable and the rear (east) elevation, and there were windows in the gables and west elevation. The purpose of this building is unclear. A small building with a single-pitched roof is attached at the south-east corner, and contains a shaped fireplace lintel with the date 1868; it was clearly a weighbridge house, although the weighbridge pit has been obscured by recent dumping.

W J Crompton, RCAHMW, 8 March 2012.