Former Tinning House at Treforest Tinplate Works

The tin house comprises 2 long parallel wings attached by link walls at either end, the gap in the centre being formerly occupied by a tramway. The walls are rubble stone painted white, the principal elevations having freestone dressings, the other sides brick dressings. The E wing has a slate roof (mostly now missing), the W wing corrugated asbestos-cement sheets. The tinning bays are housed in the E wing which is wider and higher. On the S side the E wing has an inserted wide doorway under a steel lintel, with a round-headed doorway to its R partly blocked, and a blocked opening below the 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 that was part of a former attached range S of the tin house. The W wing also has an inserted doorway under a steel lintel. The long E wall has 9 round-headed doorways with flanking windows all with stone dressings and keys, the doorways at the ends being later enlargements. On the N side the E wing has a round-headed doorway L of centre, with a window to its L cut down to make a doorway, and a later doorway and lintel to the R. The gable has 3 stepped bullseye vents. The link has a round-headed doorway now blocked, while the W wing has an inserted doorway under a lintel. The long side wall of the W wing has partly filled openings, comprising 6 doorways and flanking groups of windows. The 3 windows at the S end have square heads and are later insertions.

The tin house originally accommodated 12 tinning bays ranged lengthways in 4 groups of 3, but the group S of the centre has been removed, leaving only 9 tinning bays in the W wall facing the passage between the wings. The bays have stone jambs, wide cast iron lintels and brick stack bases. At the rear of the bays the brickwork has 3 windows in each bay that lit the former tin baths placed beneath the stacks. On the outside, as viewed from the passage between the wings, the splayed stack bases are crow stepped but the stacks have been demolished to below eaves level of the building. Segmental-headed doorways, with windows above, are between each bay. The E wing interior is divided lengthways by a continuous spine wall of rubble stone, in which there are 9 doorways with flanking windows, all with brick jambs. The roofs of both wings are composed of wrought iron trusses.