Former Tinning House at Treforest Tinplate Works

This is a former tinning house, dating from the 18th century, located within the Treforest Tinplate Works. The building consists of two long, parallel wings connected by link walls at either end; a former tramway ran through the central gap. The walls are constructed of rubble stone, painted white, with freestone dressings to the main elevations and brick dressings to the sides. The eastern wing has a slate roof, now largely missing, while the western wing has a corrugated asbestos-cement sheet roof. The eastern wing is wider and taller, housing the tinning bays.

The south side of the eastern wing features an inserted wide doorway under a steel lintel, a round-headed doorway to the right, partially blocked, and a blocked opening near the roof apex. The link wall has a round-headed doorway obscured by a flat-roofed projection, above which is the lower section of a former bullseye opening once part of a range of buildings to the south of the tin house. A similar inserted doorway under a steel lintel is present on the west wing's south side.

The long eastern wall has nine round-headed doorways with flanking windows, all with stone dressings and decorative keys; the end doorways are later enlargements. The north side of the eastern wing has a round-headed doorway, a window cut down to create a doorway to its left, and a later doorway with a lintel to the right. The gable features three stepped bullseye vents. The link wall has a blocked round-headed doorway, while the western wing has an inserted doorway under a lintel. The long western wing has several partly filled openings consisting of six doorways and corresponding groups of windows. The three windows at the southern end are later square-headed insertions.

Originally, the tin house accommodated twelve tinning bays arranged lengthways in four groups of three. However, the group to the south of the centre has been removed, leaving nine bays in the western wall facing the passage between the wings. Each bay has stone jambs, wide cast iron lintels, and brick stack bases. Brick windows behind the bays once lit tin baths situated beneath the stacks. Externally, the splayed stack bases are crow-stepped, although the stacks themselves have been demolished below eaves level. Segmental-headed doorways with windows above are located between each bay. The interior of the eastern wing is divided by a continuous spine wall of rubble stone, containing nine doorways with flanking windows, brick jambs, and wrought iron trusses supporting the roof of both wings.