Stainless steel is durable and highly customisable.

Galvanised vs. stainless steel: Which should you choose?

When it comes to buildings – and whether you're talking about structural or aesthetic elements of those structures – steel is one of the most important innovations in the modern world. Stronger and more resistant to various forms of degradation than iron, steel has served as the catalyst for everything from the bones of high-rise buildings to unique and eye-catching design components. With steel and the various tools available for forming, shaping and finishing it, architects, builders and designers have a variety of options when it comes to creating a building's framework and making sure it stands out in the eyes of those who see it.

Understanding the differences between the various types of steel available for such projects can help you make the most informed and positive choices possible, taking the unique parts of each structure into account. A good place to start is with galvanised and stainless steel, two common versions of the same material that nonetheless have some very important differences. First, let's go through a quick review of exactly what steel is, to help set the stage for identifying the differences and similarities between its galvanised and stainless versions.

A galvanised steel roof.Galvanised steel is common in a variety of construction applications.

Forging an understanding of steel

Steel is made of two key base components: iron and carbon. This makes it an alloy, which is simply a combination of either two or more types of base metals, or base metal and an element. Alloys can provide a variety of important benefits in many different applications. These range from creating stronger, more durable metals for use in construction to developing non-sparking tools, which significantly reduce the risk of explosions and other negative outcomes under specific working conditions.

Specifically, steel has a number of advantages in the world of construction as compared to other potential building materials. It is:

  • Durable
  • Strong
  • Easily recycled
  • Of a predictably high quality when forged and finished in the proper manner

Steel is also a widely used and understood alloy with a long history throughout the industrial sector and world economy, meaning many processes have been developed to manufacture it to meet a wide range of different standards and intended uses. With many functional and aesthetic applications, steel is dependable and versatile.

What is galvanised steel, and when is it useful?

Galvanised steel's defining attribute is its zinc coating, which forms a protective barrier against the combination of moisture and oxygen that can otherwise cause rust to form on the underlying metal. Rust slowly but surely eats away at steel, reducing its integrity and ultimately creating safety issues whether the steel is used in a purely functional application or is part of an impressive, customised facade or other element.

Galvanisation takes regular steel – or another metal, like iron – and coats it zinc. This process can be completed in a few different ways, which helps increase versatility and allows for many different types of steel and iron to be easily galvanised. The hot-dip galvanisation process provides a strong, relatively thick coating for large pieces of steel, while thermal diffusion galvanising is common for smaller pieces of metal, especially those that have a more complex design.

One of the most visually memorable elements of galvanised steel is its variable appearance. Depending on the specifics of the process, galvanised steel can either have a consistent finish or a spangled one. Spangle refers to the irregular shapes that appear on the surface of the metal, with different shades and level of reflectiveness. Depending on the specific project, a spangled finish can be a key element in an overall design vision.

While the galvanisation process helps protect against rust and corrosion, it's important to note that it eventually wears away – especially when exposed to high levels of acidity or to salt water. This is especially important in areas near oceans and other bodies of seawater, as well as areas that face significant exposure to acid rain.

What is stainless steel, and when it is it useful?

Stainless steel is an alloy made of iron, carbon and chromium – and occasionally other elements, such as molybdenum – that has offers significant corrosion resistance. Instead of being dipped or coated in a protective layer, as galvanised steel is, stainless steel has this defence against damage built into it. That means it can be crafted, shaped and finished in a variety of different forms without a need to take the additional step of applying the coating.

There are many different types of stainless steel available, each with different specific compositions and resultant resistance to various forms of corrosion and damage. This is useful for industrial applications where stainless steel components may face constant exposures to caustic chemicals or high temperatures, as well as in design work where the alloy could be consistently exposed to salt water or acidic environments.

Stainless steel can also be finished in many different ways, providing a high degree of customisability in terms of its final appearance. This aesthetic flexibility is especially important for facades and similar design elements that place a high priority on standing out from the crowd by offering a memorable or unique visual hook.

Which type of steel should you choose for your project?

There isn't a single, universally applicable rule that determines which type of steel is best suited for your specific project. Galvanised steel offers a unique patina from the finishing process and can capably perform in many environments for decades before appreciable rust or wear appears. However, stainless steel doesn't face the same specific weaknesses caused by salt water and acidic environments, and some varieties of this alloy can be engineered in a way that addresses those concerns. In combination with the many ways in which stainless steel can be finished, there are plenty of aesthetic and practical concerns addressed by this alloy.

To learn more about the many ways stainless steel can be deployed in your next project, get in touch with the experts at Locker today.

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