Long run metal roofing history

Long run roofing, metal roofing or corrugated iron as its more widely known, has been a staple building material in New Zealand since the earliest European settlers arrived on our shores.

Corrugated iron is regarded as an iconic ‘Kiwi as’ material, that has not only been used for buildings but has also been utilised for furniture and art.

But how did our nations most beloved material come to exist?

Just who invented corrugated iron is uncertain, as different parts of the production process were patented independently. It is widely believed that corrugated iron came into existence in the 1820s in London, with the pioneers understood to be Henry Robinson Palmer and John Walker.

There is an interesting legend about the invention of corrugated iron discussed in Stuart Thomson’s book “Wrinkly tin”*:

One day in the Phoenix Iron Works in West Bromwich, Birmingham, a sheet of metal serving as guard protection for workers on a rail-making machine came loose and was pulled into the gears of the machine. It emerged thoroughly crunched into a series of waves. The workmen repaired the guard and got on with the job, but ironmaster John Spencer noticed the crumpled sheet and picked it up. Instead of flopping around as a thin sheet of metal normally would, it remained rigid. Spencer stared at it. He stood up and leaned his weight on it, but it didn’t bend. Spencer stood still for several minutes – here was a marvellous new process which actually increased the strength of metal sheets!

Although corrugated iron cannot be accredited to a sole inventor, we do know that throughout the 19th century corrugated iron was used commonly around the United Kingdom for farm and industrial building and roofing. At the time it was primarily considered a temporary solution, however, it is now regarded as a heritage material.

In New Zealand there was an initial reluctance to use corrugated iron roofing, however, this did not last long as settlers soon discovered its versatility and ease of transport; its ready-made market expanded with every immigrant ship. The earliest examples of imported corrugated iron in New Zealand has been found on farm buildings in Matanaka, near Waikouaiti, Otago with the stables, granary and schoolhouse roofed in 1843 using Morewood & Rogers ‘patent galvanised tinned roof’. The camphouse on the slopes of Mt Taranaki is our oldest corrugated prefabricated building which came from Victoria, Australia.

The history of local roll-forming of longrun roofing begins post-WWII and was pioneered by Ness Irwin who built his own machine around 1962 in Mt Roskill. For his first four years in business he had very little local competition. After 1966, Hayes Engineering manufactured roll-forming machines in Rotorua and sold them throughout the country, with Dimond Industries in Wellington being one of their first customers. Hayes would later become a worldwide distributor.

Dimond Industries was one of the first owners of roll-forming machines that produced profiles other than corrugate in the New Zealand market. It became a dominant player in the roofing and cladding market from the early 1970’s. No roofing profile has ever been more popular throughout New Zealand than corrugated iron.

As Stuart Thomson put it in his book ‘Wrinkly tin’*:

Corrugated iron has been used in so many ways in the past that it has become a kiwi icon, with a historic and aesthetic value we are emotionally attached to.

Although housing is its biggest use, it doesn’t discriminate what it protects. We use corrugate for our barns, farm sheds, stables, dog kennels, pig pens and more.

Corrugated iron is not only one of the original do-it-yourself materials, but also one of the original recyclable materials, and good old Kiwi ingenuity has seen this beloved material used in a multitude of applications.

None are more famous than the shops of Tirau, the corrugated iron capital of New Zealand. A giant dog and sheep tower over the main street of Tirau, just two of a series of sculptures and buildings made from corrugated iron. Other highlights include the sculpture of a shepherd which stands outside the Church of the Good Shepherd on the main street, a colourful school bus with animal passengers which marks the bus stop of pupils at Tirau School, and many more corrugated iron business signs are visible all along the main street.

The name corrugated iron has been technically incorrect for over a century, and nowhere is this articulated better than in ‘Wrinkly tin’*

Just as there is no egg in eggplant, no ham in hamburgers and no duck in Bombay Duck, there is now no iron in corrugated iron – only steel.

When referring to the corrugate of the 19th century the term corrugated iron is correct, but the product made since then has predominantly been made of steel.

The corrugate that Dimond Roofing sells today is made of steel, produced by New Zealand Steel at their Glenbrook steel mill and delivered to Pacific Coil Coaters, (also known as ColorCote) for painting, before being roll-formed at Dimond Roofing branches nationwide.

There is also additional technology in the paint coatings used to colour the steel. Highly durable paint technologies, baked on to the steel at around 250C, provide additional protection to the frequently aggressive New Zealand weather. The first coat, a primer, aids the steel to prevent the onset of rust, while the second topcoat, is designed to maintain its colour and gloss in New Zealand’s high UV environment.

The same pioneering attitude seen when corrugated iron was introduced in the mid-1800s still persists today, and New Zealand is an innovation leader in the use of waterborne coatings on painted steel, reducing the impact of solvent-borne paint in our environment.

The history of longrun roofing and corrugated iron is as routed in the core of Kiwi culture as no.8 wire. Arriving in the 1840s and booming throughout the early settlements of the 19th century, it grew in the 20th and is still celebrated in the 21st. Originally coined the “temporary” material, it is showing no signs of loosening its reigns on the hearts of Kiwi’s - even when challenged with the introduction of more sophisticated profiles such as the European tray profiles, so common in today’s modern architecture - everywhere you look you will find a building featuring this iconic Kiwi favourite.

^{* Thompson, Stuart, 1929 - Wrinkly tin: the story of corrugated iron in New Zealand, Steele Roberts Ltd, Wellington}