Museum Stores, formerly Morfa Copperworks rolling mill

A long, single-storey building with a gabled roof and corrugated roof covering, topped by tall ventilators. It is constructed primarily of rubble sandstone with some brick infilling. The main elevation, to the east, has stone walls at either end, the remains of the mill buildings of 1828. The southern part contains a series of infilled semi-circular arches typical of such buildings in the period. The majority of the east elevation was formerly open, and massive timber purlins are supported on impressive tapering cast iron columns. The spaces between the columns were later infilled with brick. The north elevation has a wide arch and circular ventilation openings above, now blocked. The south elevation is rubble stone, pierced by a row of five round-headed windows (two blocked), and a further row of three smaller blocked windows above.

The interior is open to the roof for its full length, with concrete floors and industrial shelving for storage of museum objects.