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Assembly shop at former Union Ironworks

A Grade II Listed Building in Caernarfon, Gwynedd

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Latitude: 53.1375 / 53°8'14"N

Longitude: -4.2725 / 4°16'21"W

OS Eastings: 248078

OS Northings: 362448

OS Grid: SH480624

Mapcode National: GBR 5J.66MK

Mapcode Global: WH43F.BDQL

Entry Name: Assembly shop at former Union Ironworks

Listing Date: 3 May 2002

Last Amended: 3 May 2002

Grade: II

Source: Cadw

Source ID: 26548

Building Class: Industrial

Location: On Slate Quay and to the E of the former office and showroom.

County: Gwynedd

Town: Caernarfon

Community: Caernarfon

Community: Caernarfon

Built-Up Area: Caernarfon

Traditional County: Caernarfonshire

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Probably erected in the late C19 and shown on the 1889 Ordnance Survey. The building originally had a 2-span hipped roof. The Union Ironworks was founded by Owen Thomas in the early 1840s, who was joined by J.P. de Winton in partnership in 1854. The Thomas and de Winton families remained in control until 1892, after which it had a succession of owners before closure in 1902. As a foundry and engineering works it specialised in supplying marine engines and boilers, mainly to Merseyside shipbuilders, and also supplied machinery to the N Wales slate industry. By the second decade of the C20 the premises was occupied by the Kiwi Engineering Works.


Single-storey, square in plan, 5-bay brick workshop with replaced flat roof behind a coped parapet partly rebuilt. The wider central bay has a doorway with large radial-glazed overlight. Outer bays have round-headed windows recessed within round-headed bays with bullnose dressings and have small-pane iron-framed glazing. The R end wall has a single-storey added lean-to, above which are 5 windows grouped 3 2, set within arched bays similar to the front. The L end wall is similar, with an upper tier of windows grouped 2 3. At ground level are 2 blocked inserted wide cambered openings brick voussoirs on iron plates to the soffit. These originally opened to attached ironworks buildings that have been demolished.

A lower brick gabled rear wing has a corrugated asbestos-cement roof.

Reasons for Listing

Listed, notwithstanding loss of its original roof, as a C19 industrial building retaining some original character, and with the adjacent office as representing a rare-surviving small urban foundry which contributed strongly to the industrial history of N Wales. It has additional historical importance representing former industries on Slate Quay.

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