Melin-y-Bwlch forms the north-east end of a range of buildings which include two corn-drying kilns and a mill house; the kilns were incorporated into an enlarged house c1975. The mill is a two-storey structure, built of stone with a slate roof carried on two king-post trusses; it is thought to date from the late eighteenth or early nineteenth century. At its south-west end an external stair gave access to the upper floor of the adjacent kiln building.

The internal overshot wheel was fed by a slate launder from the slate-lined pond on the hillside to the north-west. The wheel bears the maker's name, W Hughes, Plas Kynaston, Ruabon. Its wooden axle carried an iron pitwheel, engaging with an iron wallower gear on the wooden upright shaft, and the latter carried an iron great spur wheel meshing with two iron stone nuts with wooden teeth. A crown wheel of eight sections secured to the top of the spur wheel drove a square-section horizontal shaft with pulleys for the sack hoist and a wire machine. the latter remains in situ on the south-east wall, and there is an oats machine and husk cupboard at the north-east end of the mill. Other belt drives powered an oats sifter and its fan. On the upper floor there are two pairs of millstones, one pair of French burrs supplied by Barron and Son, Gloucester, and a monolith pair for oats. The sack hoist remains in situ in the roof structure.

Information from notes by A J Parkinson, 1975.
W J Crompton, RCAHMW, 2 April 2014.