Rhydlydan Mill is a nineteenth century corn mill. It has an internal overshot wheel, overdrive spurwheel, three pairs of millstones and much surviving machinery, e.g. sack hoist, smutter and flour-dressing machines. It has two storeys with an attic constructed of stone with brick dressings and eaves courses, under a slate roof.
The mill was built in c.1845, possibly on the site of an earlier mill. A later drying kiln of similar materials is attached to the east end. The date 1845 painted internally is credible.
The waterwheel is set on a large iron axle and has iron hubs spokes and shrouds; the buckets and soleplates have gone. The all-iron pitwheel meshes with an all iron wallower (unusual in that one wheel would normally have wooden teeth). At the top of the main shaft is a wooden great spur wheel, unusually with a double row of wooden teeth, offset, driving stone nuts, also wooden, with similar rows of wooden teeth. The three pairs of millstones are driven from above. Two bear the plates of E.Davies & Sons, Liverpool, and Kay & Hilton, Liverpool. The drive to a flour dresser and a boulter is to the rear of the floor.
The ground floor has a doorway into the kiln, which is also accessible from the stone floor. The funnel type grain-drying kiln has a brick substructure and the scanty remains of a perforated iron tiling drying floor above, supported on iron joists.
The attic storey of the mill has a raised walkway between the wooden bins, with trapdoors. There is a wooden sack-hoist and the ties of the roof trusses are arched to allow passage beneath.
Condition of the mill as noted by RCAHMW in 1968 was 'excellent'; by 2013, the mill was noted as having a derelict air and the roof is begining to leak; windows, doors and some of the gable weatherboards are missing and water ingress is causing damage to internal floors and woodwork.

(Sources include: RCAHMW site visits 1968 and 2013; Cadw listing database)

B.A.Malaws, RCAHMW, 23 October 2013.