Galvanizing in the public realm

Modern life can have a habit of being fast, furious and disposable. Long-term thinking is often eschewed for the here and now. We all share a responsibility to balance value for money today with decisions that will remain appropriate for future generations. Material choices, even on the most modest items, can make a tangible difference, as Iqbal Johal from the Galvanizers Association explains

Back to the future – 170 years young

In 1742, a chemist named Melouin presented a paper to the French Royal Academy in which he described how a zinc coating could be obtained on iron by dipping it in molten zinc. Interest in Melouin’s discovery spread quickly throughout scientific circles and the first application was to use molten zinc as a cheap protective coating for household utensils.

This period also saw the invention of an engineered material that would help to embed ‘galvanizing’ into the language of people across the entire globe. In 1829 Henry Palmer of the London Dock Company was granted a patent for “indented or corrugated metallic sheets”, his discovery would have a dramatic impact on industrial design and galvanizing.

The London Dock, which had only been built in 1805, was busting with the strain of wine, spices, coffee, cocoa and wool arriving into the world’s consumer capital. Henry Palmer was given the job of overseeing the construction of a new dock. To solve the problem of roofing massive new warehouses, he came up with the invention of lightweight corrugated iron sheets. The corrugations made the sheet more rigid so that less framing was required to support it as a roofing material. The first building to use corrugated iron was the Turpentine Shed in 1830. It was praised for its elegance, simplicity and economy.

However, it was soon realised that the iron corroded quickly – a problem to be solved over a period of time by the introduction of hot dip galvanizing the corrugated sheets. Although uncertain, the first use of galvanized corrugated iron is believed to have been for the Navy at Pembroke Docks, Wales in 1844. The use of the material soon spread to the railway industry, being used to span the 212 foot roof of Birmingham’s “new Grand Central Railway Station” in 1854.

It was also used for the other landmark station of the time, Paddington, which was designed by Isambard Kingdom Brunel and opened in 1854. Brunel designed a building with 120,000 sq ft (36,650 sq m) of galvanized corrugated iron sheets that enclosed two-thirds of the vaulted roof. The sheets were used in such a way with corrugations at right angles to the roof, so that the whole structure would stiffen. This made the roof a very early example of a stressed skin design. The great advantage of corrugated iron was now coming to the fore, its lightness offered builders the ability to build very large spanned buildings with correspondingly light supporting structures and its use spread across the world.

Galvanizing today

The intervening time has seen iron replaced with steel and galvanizing continues to play an important role away from the limelight given to many other processes.

Today’s architects use it because of its unique properties, as detailed by John Parker, ABK Architects:

“Galvanizing gives texture to steel, it has a certain materiality and reflects light in a certain way, not found in stainless steel or aluminium.”

Others may prefer its longevity and the fact that it provides an alloyed coating.

Perhaps it’s the honesty of the coating – the fact that its final aesthetic is based on a mixture of chemistry, steel thickness and design, setting it apart from the over-engineered and inert coatings of more recent times.

A proven, honest and sustainable coating that has not lost its links to the alchemists that created it many hundreds of years ago.

Rob Mulholland, Skytower, Airdrie, Scotland

Skytower was commissioned by Forestry Commission Scotland for their new woodland park at Rawyards in Airdrie.

The sculpture is made from cut lengths of metal rod which have been shaped to resemble sticks and willow. Each metal rod is welded and interwoven, with over 6,000 welds and 1,400m of steel rod. The sculpture was galvanized in one complete section with a total length of 6m, and stands silhouetted against the skyline overlooking Central Scotland.

It is purposefully geometric with references to standing monolithic stones and historical architectural structures. Skytower captures a moment of flux frozen in time – a sudden gust of wind, an unstoppable force of nature rips through the fragile structure scattering the branches and reshaping the tower.

Eco Arc Architects, Lancaster Cohousing Project

Currently the largest certified Passivhaus housing project in the UK, containing 23 three-bedroom family houses, 12 two-bedroom family houses and 6 one-bedroom flats. It has achieved Code for Sustainable Homes Level 6 (carbon neutral). The community owns 2.5 ha of land, including woodland, which it is managing and restoring with native plants.

The design brief provided for a 100 year design life, rather than the 60 years typically used for new housing. For this reason, extensive use of galvanized steel has been made on external finishes and external works such as balconies, porches and staircases.

Proctor and Matthews Architects, Hargood Close, Colchester

Hargood Close is a supported housing scheme in Colchester for vulnerable people in need of emergency temporary accommodation. The development provides a mix of apartments, including studios, one- and two-bedroom dwellings, as well as family houses. The brief called for a mix of dwelling types that would provide more flexible options to help staff respond to the differing living requirements of changing tenants.

All materials for this project have been chosen to reflect the need for attractive surfaces with a domestic feel that at the same time are very durable and robust. To complement the natural warm tones of the brickwork of the main elevations the access walkways feature a galvanized steel structure with perforated and glazed infill panels.