Corrugated iron has been one of the characteristic building materials in New Zealand for over 150 years. It is technically light steel sheet that has been galvanised (treated with a coating of zinc on both sides) to prevent rusting, then rolled into corrugations at either 3 or 5 inches (76 or 127 millimetres). First produced in English steel mills in the 1830s, it was regarded as suitable only for temporary buildings.
Early use in New Zealand
In the goldfields of California, Australia and New Zealand there was a need for speedy construction, and corrugated iron was just the material: weatherproof, light, portable, and easy to put up. R. & T. Haworth started producing galvanised iron in Dunedin in 1864, from imported steel plate.
As the population became settled, more permanent buildings were built, and corrugated iron was generally used only for those parts not immediately visible. Many houses and commercial buildings had imposing wooden or stone frontages, but the sides and back were utilitarian – summed up as ‘Queen Anne in the front, and a meat safe at the back’. 1 In between there was usually a lot of corrugated iron.
Corrugated iron was widely used in rural areas as a general-purpose building material. Most farmers could readily build a frame for a shed or hay barn, and then clad it with corrugated iron. Because the sheets of iron had to be purchased and then transported to the farm, they were often re-used once a temporary building was abandoned.
Tramping huts were traditionally made of corrugated iron. Before the days of helicopter transport, it had to be carried to the site – often a slow trip with an awkward load.
A shocking experience
Working in a remote part of the Buller Coalfield in 1938, geologist Harold Wellman saw a loose sheet of corrugated iron lying by the Stockton electric railway. Needing to make an outdoor chimney, he picked it up and started to walk back to camp with the sheet on his back. Unfortunately the iron touched the overhead power lines, and he got an electric shock that he never forgot.
From the early 20th century onwards corrugated iron was mainly used as a roofing material, traditionally painted red or green. Many immigrants recorded their surprise at seeing the colourful iron roofs when they first arrived. When the 1935 Labour government started an active programme of house construction, they discouraged the use of imported components, so tiles and other roofing materials gradually replaced iron.
Corrugated iron renaissance
In the 1970s New Zealand Steel started to produce a variety of flat and corrugated products that have been widely used for roofing. In the 1990s, these reappeared as a cladding material, as part of a local architectural style based on functionalism and nostalgia.
Because it is flexible and readily shaped, corrugated iron has enjoyed a renaissance as a material for modern sculpture.