Corrugated iron

"The first iron sheets made in Britain were rolled at the end of the 18th century for the recently introduced tinplate industry."

The corrugation of sheet iron increases the strength of the material significantly. It is claimed in Loudon’s (Encyclopaedia of Cottage, Farm
and Villa Architecture 1833) that “Walker of Rotherhithe” was the inventor of corrugated iron. However the first patent connected with corrugated iron was granted to Henry R Palmer of the London Docks, a London civil engineer, in 1829. Palmer did not claim as his invention the mode of forming sheets “the means of producing such forms being well known”. But he claimed originality for its application to roofs and walls.

http://www.ihbc.org.uk/context_archive/44/Corriron_dir/Corriron_s.htm

"The common term 'corrugated galvanised iron' is used to describe two different materials, galvanised wrought iron and galvanised mild steel. Until very late in the nineteenth century, all corrugated galvanised iron was made from wrought iron, but from 1890 to 1910 improved methods of steel making and processing led to the complete replacement of wrought iron by mild steel. "

"The strengthening effects of corrugating or crimping flat sheets have been known for centuries, but a successful technique for corrugating did not appear until the early 1840s. At first the grooves were produced by pressing and this method continued in use throughout the nineteenth century. Grooved rolls were in use by 1845, although the method of achieving uniformly corrugated sheets was not developed until much later."

http://www.heritage.vic.gov.au/pages/pdfs/Roofing.pdf

Tylecote 1976 'A history of metallurgy' p133 states that 'The idea of stiffening iron sheet had been introduced by R. Walter of Rotherham in 1828, and hot
zinc dipping was patented in 1836. But does not give a date for the combination of the two to produce 'corrugated iron'.

http://lists.asu.edu/cgi-bin/wa?A2=ind9905&L=histarch&T=0&F=&S=&P=8240

"the now rare zinc coated wrought iron of the nineteenth century ... was replaced by mild steel from the 1890s. The ‘gal iron’ that became such an important part of the Australian vernacular is in fact galvanised corrugated steel."

"Today, however, the most popular and best-promoted corrugated roofing is Zincalume® ( (55% aluminium, 43% zinc and 1.6% silicon) or the factory coated version of Zincalume®, Colorbond®. These materials look and behave quite differently from traditional galvanised sheet. Galvanised sheet is still available today but is a rather different product from the hot dipped sheet produced up to the 1960s."

http://www.heritage.vic.gov.au/page.asp?ID=183