Understanding the Difference Between G60 and G90 Galvanizing for Structural Metal Deck

Galvanizing is a widely used protective coating applied to structural metal deck to enhance its durability and resistance to corrosion. Two common galvanizing specifications used in the industry are G60 and G90. In this blog post, we will explore the differences between G60 and G90 galvanizing and their significance when it comes to structural metal deck applications.

Galvanized Metal Deck

Galvanizing Process:

Galvanizing involves coating steel with a layer of zinc, which forms a protective barrier against corrosion. The process typically involves cleaning the steel surface, immersing it in a bath of molten zinc, and allowing the zinc to bond with the steel through a metallurgical reaction. This results in a zinc coating that provides long-lasting protection to the underlying metal.

G60 Galvanizing:

G60 galvanizing refers to a zinc coating with a total weight of 0.6 ounces per square foot. It is a common specification used in many construction applications, including structural metal deck, also referred to as roof deck. The G60 coating provides a good level of corrosion resistance and durability. However, it may be more suitable for interior or mild environmental conditions where the exposure to corrosive elements is relatively low.

G90 Galvanizing:

G90 galvanizing, on the other hand, refers to a heavier zinc coating with a total weight of 0.9 ounces per square foot. This specification provides a thicker and more robust layer of protection compared to G60. G90 galvanizing is often preferred for structural metal deck applications in more corrosive environments, such as coastal areas or industrial settings, where the risk of corrosion is higher due to exposure to saltwater, chemicals, or pollutants.

1.5B roof deck Galvanized

Differences in Corrosion Resistance:

The key difference between G60 and G90 galvanizing lies in their respective levels of corrosion resistance. The thicker zinc coating of G90 provides enhanced protection against rust and corrosion, making it more suitable for applications where the metal deck will be exposed to harsher environmental conditions. G90 galvanizing can extend the lifespan of the structural metal deck, reducing the need for premature repairs or replacement due to corrosion-related issues.

Cost Considerations:

While G90 galvanizing offers superior corrosion resistance, it is generally more expensive compared to G60. The additional zinc required for the thicker coating contributes to higher material and coating costs. Therefore, it is essential to consider the specific project requirements and environmental factors when selecting between G60 and G90 galvanizing. It may be more cost-effective to opt for G90 galvanizing in environments with a high risk of corrosion, whereas G60 galvanizing may be sufficient for less corrosive conditions.

Consulting Industry Standards and Specifications:

To ensure the appropriate galvanizing specification for structural metal deck, it is recommended to consult relevant industry standards, building codes, and project specifications. These guidelines will provide specific recommendations based on factors such as environmental conditions, load requirements, and design considerations. Engaging with experienced engineers, architects, and galvanizing experts can help in making informed decisions and selecting the optimal galvanizing specification for your project.


Understanding the differences between G60 and G90 galvanizing is essential for selecting the most suitable coating for structural metal deck applications. While G60 provides adequate protection for many interior or mild environmental conditions, G90 offers enhanced corrosion resistance for more demanding environments. Careful consideration of project requirements, cost considerations, and adherence to industry standards will ensure that the selected galvanizing specification provides long-lasting durability and protects the structural integrity of metal deck systems, reducing maintenance and replacement costs in the long run.

Contact us for G60 and G90 Galvanized Structural Metal Deck

As a leading metal deck supplier, we take pride in offering exceptional products and unmatched service. When it comes to G60 and G90 galvanized structural metal deck, our knowledgeable team is ready to assist you. We understand the significance of selecting the right metal floor deck type that aligns with your project's specific requirements, and we are committed to helping you make a decision that will offer you the very best results. 

Contact Oates Metal Deck today by calling 713-475-0427 or filling out our contact form below to get started.