Former Casting House and Workshop at Treforest Tinplate Works

Cadw's description

Location

At the N end of the former tinplate works.

History

The Treforest Tinplate Works was established in the late eighteenth century, but the surviving works dates from its rebuilding in 1834-5 by William Crawshay II of the Cyfarthfa Iron Co, although it was managed by his son Francis Crawshay. It coincided with the beginning of the accelerated growth of the British tinplate industry that continued throughout the remainder of the C19. Production began in 1836 and by 1842 it had fineries for converting pig to wrought iron, 2 mills for rolling the iron into sheets, furnaces for reheating and annealing the iron, and 2 tin furnaces in which the plates were immersed in a bath of molten tin. Power was provided by 8 waterwheels. The Tithe map of 1846 shows that the works was at that time all housed within what later became known as the rolling mill. A separate detached block to its N was probably the foundry mentioned in an inventory of 1842, but was probably demolished in the subsequent expansion of the works.

The works was considerably expanded c1854, again representative of the growth of tinplate manufacture in S Wales in the 1850s. Most of the buildings on the site, including the tin house and smithy, belong to this date, and all are shown on the 1875 Ordnance Survey. In 1876 the works was described as having 5 mills, in 1893 10 mills, while the extant tin house was designed for 12 furnaces, superseding the 2 listed in 1842. In 1896 the works was leased to Waterhouse Brothers of Bradford, but output declined in the C20. Its final owner was Richard Thomas & Co. Production ceased in 1939 when the works had 4 working mills. In 1941 the works was requisitioned for storage by the Ministry of Supply. In 1946, if not earlier, the machinery was removed and 2 large blocks N and E of the rolling mill were demolished under the Tinplate Redundancy Scheme. The site was then sold to the South Wales and Monmouthshire Trading Estate.

The manufacturing of tinplate required iron bars to be rolled into thin sheets, which were then trimmed, cleaned in an acid bath (known as pickling), annealed, re-rolled to create a smooth surface, and again cleaned and annealed before being dipped in molten tin. The sheets were subsequently polished in bran and boxed ready for dispatch. From the 1850s the sheets were rolled in the surviving rolling mill, and were then pickled, annealed and re-rolled in ranges to the E and N that have now been demolished. Tinning, polishing and packing were undertaken in the surviving tin house. Further ranges to the N and E were workshops used for various maintenance activities.

The casting house and workshop were built c1854, part of the large-scale expansion of the works in this period. A keystone is dated with the initials WC, although the date is now illegible. It has been said to read 1834, but the present building was not built at that time and is therefore either re-used from another building or, more likely, reads 1854.

Exterior

Comprising 2 single-storey ranges placed end to end and now joined by a C20 link. Both are of rubble stone and having round-headed openings with stone dressings to the E elevation and brick elsewhere. The S range has a slate roof, now mostly missing, the N range an asbestos-cement roof.

The S range is lower. Its S gable end has a doorway flanked by windows, and with 3 stepped bullseye vents in the gable, all now blocked. The E wall has 2 tall doorways flanked by pairs of windows. The W side wall is similar but between the windows are bullseye vents. The N gable end has 3 bullseye vents. A central round-headed doorway has been altered by inserting a lintel below the head, and has a window inserted immediately upper R of it. Round headed outer windows have been cut down to make doorways. A corrugated C20 link is between the 2 ranges.

The S gable end of the N range has been demolished. The E wall has a central round-headed doorway with dated keystone, to the L and R of which are lower doors flanked by windows, all with stressed keys and imposts and the windows with stone sills. The N gable end has a doorway flanked by windows and 3 bullseye vents, all blocked. On the W side is an added continuous lean-to, which has blocked segmental windows and an inserted wide doorway. The eaves have been heightened in brick. A blocked doorway is in the N end and an inserted doorway in the S end wall.

Interior

Both ranges have wrought iron roof trusses. The original W wall of the N range has 3 wide doorways flanked by 4 narrower and lower doorways.

Reason for designation

The surviving buildings at the Treforest Tinplate Works constitute the most complete group of buildings in the industrial style developed in the iron and related trades of S Wales from the early C19. They form one of the most complete groups of tinplate works buildings of the C19, an industry of national importance dominated by S Wales. Listed II* primarily for group value.