Galvanised steel, the benefits

Feb 27, 2019

When to go galvanised:

Thanks to its high resistance and flexible nature, galvanised steel is the material of choice for a range of construction projects.

Most common applications include support systems such as building frames, beams and roofing applications and it is not only widely used but highly regarded by construction professionals alike.

Its protective covering is also efficient in coastal environments, where exposure to salt and sea water can have a significant impact causing corrosion and rust. Whilst over time the conditions will have an effect on the steel, the zinc component helps slow down this reaction, meaning galvanised steel is able to fulfil its role when galvanised and utilised correctly. Similarly, its performance is often considered unrivalled when it comes to freezing conditions.

Despite its strength and versatility, galvanised steel isn’t always the best option. For example, it’s rarely used in underground projects as in order to prevent premature corrosion, zinc relies on surface oxide films which cannot be formed without the presence of oxygen. Hot dip galvanisation is also an unsuitable protection method in conditions where metal comes into contact with acid.

The benefits:

Enhanced corrosion protection

As anyone with experience in non-galvanised steel knows, rust jacking can have a significant impact on the integrity and stability of brickwork. The rate of corrosion in galvanised steel is considerably less. To put this into context, across London the average steel corrosion rate varies between 0.5 – 2.5 (µm/year), and the average lifespan for galvanised coating ranges between 34 and 170 years. See Galvanizers Association Corrosion Map. From a financial perspective, reports show that the cost of corrosion across Europe is over 3% gross national product, a considerable figure.

The method of hot dip galvanisation guarantees corrosion resistance with three layers of protection. The first, known as barrier protection refers to the bonding of the zinc layers, helping to prevent damage. The second is the zinc patina formation; environmental exposure of zinc reduces corrosion risk with its creation of surface by-products. Finally, is cathodic protection, whereby the zinc naturally shields and protects the steel beneath it.

Durable & hardwearing

With guaranteed full surface coverage thanks to the immersive steel dipping process, and an even distribution of protective covering the double dip galvanised steel is abrasion resistant, hardwearing and built to last. With a bond strength around 8 x higher than paint and intermetallic layers stronger than substrate steel it withstands shipping, storing and handling damage with ease.

Cost effective

With a low initial outlay and significantly lower lifetime costs, galvanised steel is proven to be considerably more cost effective than alternative steel protection coverings. Hot dipping is traditionally carried out by machine and is therefore significantly less labour intensive than painting. Its strength, versatility and durability also mean for reduced maintenance works over the course of its life.

Faster construction

 Unlike other protection methods, galvanisation can be completed within hours and the finished product is available for immediate use. With no requirement for surface preparation or other necessary checks and touch-ups, galvanised steel is ideal in an industry where time is money and projects delays can prove costly.

Greater sustainability

Galvanised steel is renewable and therefore has no detrimental environmental impact. This is due to the entirely recyclable properties of both zinc and steel, the two required elements that make up the process of hot dip galvanisation. It is so sustainable in fact, that enough energy is reserved for every one ton of hot dipped, galvanised steel to support a family’s needs for a number of weeks. With little to no maintenance required thanks to its considerable durability and therefore no extra resource required to extend its longevity, environmental damage is of little concern when using this kind of steel.

Enhancing its life:

Whist the requirement to clean galvanised steel surfaces will vary greatly dependent on usage, its worth noting that it can increase product life if done correctly. Method and material will depend solely on the type of markings, for example, where light staining occurs, household cleaning products might be suitable. However, for something more significant, say spray paint, paint thinner or a similar alternative will be required. For more detailed information on the cleaning of galvanised steel visit American Galvanizers Association.

Another consideration with galvanised steel is the formation of wet storage stain, a residue most commonly caused by the restriction of airflow to the zinc, resulting in surface staining. It’s a reactive reaction, and can also come into force when the freshly galvanised items come in to contact with certain environmental conditions. Whilst cleaning can remove staining, its worth considering ways in which you may be able to reduce the risk. For example, stacking efficiently, leaving sufficient breathing room between items and storing only in dry conditions are all proven methods that help prevent damage of this kind.

Additional resources:

• Galvanizers Association: Providing advice, resources and information around hot dip galvanisation
• Hot dip galvanized coatings on fabricated iron and steel articles specification standard – EN ISO 1461.

Let us support you

As part of our ongoing commitment to provide top quality products to our customers, we partner with leading industry suppliers who we know we can rely on. With over 50 years’ experience in steel lintel supply, and the only manufacturer who hot-dip galvanise after fabrication, Birtley Group are a fantastic choice when it comes to steel supply.  As members of the Galvanisers Association (an organisation who actively promote high standards of technical efficiency in the industry), we’re confident in their ability to deliver for our customers. With a range of galvanised lintels available for next day delivery as standard* we can help you keep your important projects on track. Contact our team for more on Birtley super galvanised, and ultra-galvanised steel today!