5 Most Common Steel Coatings Available in Australia
IN BRIEF
When it comes to commercial steel buildings like warehouses, workshops, and factories, choosing the right steel coating is crucial to prevent corrosion and extend the steel’s lifespan. Here are the five most common steel coatings used in Australia to protect commercial sheds, steel shade structures, and other industrial buildings.
CONTENTS
1. Hot Dip Galvanising
Hot dip galvanising (HDG) is a foundational steel coating method, offering robust corrosion protection by coating ferrous materials with zinc. This process involves immersing the steel in a pickling bath of hydrochloric acid, then submerging it in hot molten zinc, where a reaction with carbon dioxide forms zinc carbonate. This hard coating shields the steel from environmental damage, making it ideal for long-term, heavy-duty commercial use, such as large-scale warehouse projects.
2. Zinc-Rich Primers
Often applied as a base coat, zinc-rich primers deliver an initial layer of protection and serve as a solid foundation for additional coatings. Applied as paint in several layers, zinc-rich primers provide substantial resistance but can be outperformed by the comprehensive immersion process in hot dip galvanising. For effective adhesion, abrasive blasting is performed on the steel surface before primer application, removing rust and contaminants for an even and secure bond.
"When you’re planning your building, your engineer will specify the required coatings and these are usually specific to the environment the structure is built in. For example, in coastal areas, a special 3-coat system consisting of polyurethane and epoxy coatings may be required after galvanising."
- Shane Barker, Pre-Construction Manager
3. DuraGal®
DuraGal® by Infrabuild is a pre-galvanised product range that includes steel angles, flat bars, channels, and tubular options, designed for superior corrosion resistance. Adhering to AS/NZS 4792 standards, each piece is coated inside and out, offering comprehensive protection. However, any welding can compromise the coating and create vulnerabilities in the structure. DuraGal® remains a trusted solution for steel construction services that require pre-treated steel with efficient protection.
4. Polyurethane Coatings
Polyurethane (PU) coatings are ideal for both interior and exterior components, providing a durable, colourful finish that withstands water, abrasions, chemicals, and UV exposure. PU coatings are usually sprayed on in multiple layers, which enhance durability and are suited for smaller components in machinery or equipment within a steel structure. This type of coating is less common for entire buildings but provides an excellent protective finish for specific applications.
5. Epoxy Coating
Typically applied over a zinc primer, epoxy coatings serve as an additional barrier with strong adhesion properties, especially beneficial where ideal surface preparation may be challenging. Known for their adaptability, epoxy coatings are often used in marine applications due to their ability to cure on damp surfaces and even underwater, making them a reliable choice for structures exposed to high moisture levels.
Selecting the Right Steel Coating for Your Structure
Every commercial steel construction service has unique requirements based on environmental conditions and project goals. Selecting the right coating ensures durability and maximises the structure’s lifespan.
At Steelcorp, we collaborate closely with your engineer to provide tailored coating solutions that protect your steel investment, from warehouse projects to custom commercial sheds.
