Ynys Pandy felin lechi

Built of uncoursed but carefully jointed stone rubble, originally with a slate roof which was removed in 1906. The building stands on an artificial platform held by retaining walls, and is of 3 storeys, developing into 4 at the W end. It is rectangular, 4 bays wide, and 9 bays long. Each bay has large semi-circular headed arches constructed of dressed voussoirs with keystones externally, the walls diminishing in thickness at each floor level to provide a seating for the Baltic pine floor joists, now missing. The E gable has a decorative feature around the top window. The original tramway is carried on a raised curving formation to the central opening on the S side, whilst the incoming water ran parallel and outside the S face of the building up to the entry point at the centre. Rubbish was carried out from the N side by a further tramway at 2ft (60.96cm) gauge and tipped to the NE of the mill.

The internal working arrangements of the mill are not known in detail, and it appears that there was some logical working progression down of material through the mill. A deep cross trench at the centre contained the leet driving the main drive water wheel, the water conducted in from the parallel channel on the S side.