Former Casting House and Workshop at Treforest Tinplate Works

The Former Casting House and Workshop at Treforest Tinplate Works is a Grade II* listed building consisting of two single-storey ranges placed end to end, now connected by a 20th-century link. Both ranges are constructed of rubble stone, featuring round-headed openings with stone dressings on the east elevation and brick on other sides. The southern range has a slate roof, which is mostly missing, while the northern range is topped with an asbestos-cement roof.

The southern range is lower in height. Its south gable end has a doorway flanked by windows and three stepped bullseye vents in the gable, all of which are now blocked. The east wall contains two tall doorways with pairs of windows on either side. The west side wall mirrors this arrangement but includes bullseye vents between the windows. The north gable end features three bullseye vents. A central round-headed doorway has been modified by inserting a lintel below the head, with a window added immediately to the upper right. Round-headed outer windows have been cut down to create doorways. A corrugated 20th-century link connects the two ranges.

The south gable end of the northern range has been demolished. The east wall has a central round-headed doorway with a dated keystone, flanked by lower doors and windows, all featuring stressed keys and imposts, with stone sills on the windows. The north gable end has a doorway with windows on either side and three blocked bullseye vents. The west side has an added continuous lean-to with blocked segmental windows and a wide inserted doorway. The eaves have been raised with brick. There is a blocked doorway at the north end and an inserted doorway at the south end wall.

Both ranges are supported by wrought iron roof trusses. The original west wall of the northern range has three wide doorways flanked by four narrower and lower doorways.