Unappreciated materials (1): Corrugated iron

Latest posts by Prof. Mike Ashby (see all)

corrugated-ironSome materials catch headlines, are held in awe, but not all. Some get little respect despite, in some cases, having changed the world. They have become commonplace, anonymous, ignored and (particularly if they are cheap) cast aside when no longer wanted. If they had feelings, they would be hurt. This blog is the first in a series designed to draw attention to their plight…

Australian vernacular: wood framed, galvo-roofed housing enabled the rapid development of the British coloniesOn 28th April 1829, one Henry Robinson Palmer registered British Patent No 5786 for a new material that he called “corrugated iron”. Corrugated iron, more precisely defined, is zinc-dipped (“galvanized”) mild steel sheet that has been rolled through gear-shaped rollers to create a repeating sinusoidal profile. The profile gives the sheet bending stiffness about an axis normal to the corrugations, allowing self-supporting wall panels. If the sheet itself is given additional curvature about this second axis it becomes a shell, stiff and strong about any axis of bending, allowing wide-span roofing without the need for rafters and purlins.

A doubly-curved galvo roof panel. Many new materials never find profitable application. Those that do generally face stiff competition when first launched—it is often said that it takes 15 years to bring a new material to commercial success. Not so corrugated iron. Its take-up was almost immediate. By 1830 corrugated iron was in use for commercial buildings, providing cladding for the walls and light, wide span roofs described at the time as “the lightest and strongest roof (for its weight) that has been constructed by man since the days of Adam”. Within two years the new material was being exported from Britain to its colonies for a rapidly increasing number of applications. Prefabricated “galvo” structures, designed for export, were first assembled and opened for viewing by the public before numbering the parts, disassembly, packing and shipping to the colonies. Small homes, larger ware-houses and even entire small towns were prefabricated and exported in a form that allowed easy transport and rapid reassembly. Corrugated iron became the construction material of agricultural communities, and the ease of disassembly made it easy to relocate or recycle entire buildings. More recently it has become the material of emergency and disaster relief structures, capitalizing on its portability and rapid assembly.

For the next 120 years corrugated iron was the material of choice for cheap portable (meaning pre-fabricated) structures as humble as a stand-alone toilet or as elaborate as a church, hotel, or customs house. It became the material for the roofs of railway terminals and the hangars of airships. But the consequence of this is that corrugated iron became anonymous, simply part of the landscape, and unattractive to architects because of its associations of cheapness. The versatility, cost effectiveness, and reusability of the material become obscured by the fog of adverse public perception: corrugated iron had become synonymous with the cheap, the temporary, and the ugly; a material fit only for use in agriculture, village dance-halls, and small-town movie houses.

The 1950s brought the low point for corrugated iron. It continued to provide cheap, durable, easily erected structures where disaster of poverty demanded it, but this is not an image that attracted award-seeking architects or wealthy clients. And at the cheap end of the market there was new competition in the form of “fibro”—15% asbestos-reinforced cement, widely available both as flat and as corrugated panels.

Galvanized iron in the 21st centuryThis particular competitor disappeared abruptly in 1980 with the first of many major asbestos-related law suits. It was at about this time that the visual qualities of weather and corroded corrugated iron and its associations not of slum development but of the early settlers’ history and agricultural achievement began to appeal to architects. Since then corrugated iron has, to an extent, been rehabilitated and become appreciated once more for what it is: a cheap, durable structural material, easily transported, assembled, disassembled, and reused with remarkable versatility.

Further reading

Corrugated Iron – building on the frontier” by Adam Mornement and Simon Holloway, Frances Lincoln Ltd. London. ISBN 978-0-7112-2654-8. (A beautifully illustrated biography of a versatile and characterful material.)

2 thoughts on “Unappreciated materials (1): Corrugated iron

  1. Mick Farrell

    So pleased to come across your blog in my research for an affordable housing scheme in Norfolk. Our aim is to produce prefab sections to be assembled on site by local housing associations. Are you aware of any similar projects that we could visit?
    With many thanks for your corrugated support!
    Mick Farrell

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *