What is the Advantage and Disadvantage of Galvanized T-Steel

Choosing a metal roof for your building doesn’t end there; you must also decide on the type of metal roof you want. Galvanized steel, aluminum, and copper, are some of the metal materials property owners use for their buildings.

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People use galvanized steel for a lot of roofing applications. However, there are several things to consider before deciding on a galvanized metal roof. This step is critical, as it will influence your roof’s performance. In this piece, we will discuss the details of a galvanized roof and the reasons why you should or shouldn’t go for it.

What Is Galvanized Steel? 

Out of all the types of steel available on the market, galvanized steel is a very popular option—one of the most popular, in fact. Manufacturers produce it by coating steel with zinc. The application of zinc protects the inner layer of steel from corrosive factors. This protection extends its lifespan, resulting in a premium-quality and long-lasting metal.

This type of metal is versatile, and as a result, people use it for different projects and industries, including construction, agriculture, and automotive. Some examples of what people use galvanized steel for are construction materials, pipes, wires, and tubing. 

Using galvanized coils and sheets for roofing was a common practice before Galvume was introduced to the metal roofing industry. In the early s, more than 90% of the industry started using Galvalume substrates instead of galvanized substrates. This switch happened because of its superior resistance to corrosion and its exceptional durability.

It is common practice for people to refer to galvanized metal sheets or coils by their coating weight name. 

Applications of Galvanized Steel Metal 

Galvanized steel is used almost everywhere, from water pipes to cars to nuts and bolts. A very common application is modern steel-frame structures. People also use it for walkways, staircases, ladders, and others. 

Below are some of the industries where people apply galvanized metals: 

• Construction industry: It is a popular choice in the construction industry due to its durability and aesthetic appeal. People use it for commercial and residential buildings. Galvanized steel gives buildings a shine that gives them a modern look, making it prevalent in contemporary architectural designs. Aside from using it for extensive structures, they use it for fencing, rails, poles, and gutters, to mention a few.
• Solar industry: Hot-dipped galvanized steels are commonly used in solar projects because of their corrosion resistance. Aside from that, it is a popular choice because it is environmentally friendly, as it doesn’t have any emissions and can last for decades, even without maintenance.
• Telecommunications industry: lines are pretty high and, as a result, difficult to reach. This makes them a bit challenging to maintain. Using hot-galvanized steel on equipment boxes and wiring reduces the need for maintenance and the chances of damage.  
• Automotive industry: Although zinc-coated car bodywork was limited to luxury automobiles until the s, it is now a standard in the auto industry. Galvanized steel’s resistance to rust helps manufacturers give their customers anti-rust warranties. Hence, they use galvanized steel to make the ‘body-in-white’ of cars, which constitutes about 80% of the body. 

Advantages and Disadvantages of Galvanized Steel

Advantages

• Malleability: Galvanized steel is a malleable metal. It can bend and form more easily than other metal types. For this reason, manufacturers often use them in stamped vent flashings or stamped metal shingles. This property can also make roll-forming galvanized panels slightly neater and allow for more uncomplicated cutting and shaping at installation.
• Rust resistance: Steel is highly rust-prone because of its iron elements. However, galvanized steel is resistant to rust due to its zinc coating. Zinc acts as a cushion that protects the steel from the action of oxygen or moisture. 
• Longer lifespan: It has a life expectancy of over 50 years in a moderate environment. However, when you expose it to water a lot, it can last for as long as 20 years or a little more. It also doesn’t require maintenance. 
• Low initial investment: Unlike most treated steels, galvanized steel has a low initial cost. Additionally, it is ready to use as soon as it arrives. It doesn’t need any additional surface preparations, coatings, inspections, or other processes, which helps to save money that property owners could have spent on those things.
• Suitable for animal sheds: One of galvanized steel’s most outstanding benefits is its suitability for the construction of animal sheds. Unlike Galvalume, which is not ideal for building animal shelters. The Galvalume reacts with the ammonia gas from the animals’ wastes over time. This reaction disintegrates the Galvalume coating and damages the metal. Despite the galvanized steel’s suitability for animal sheds, it is best to consult the manufacturer before putting one on the building for your animals. They might have advice that will be beneficial for your design.

Disadvantages

• Lack of substrate warranties: A significant disadvantage of this metal type is that the substrate has no warranty. Many manufacturers do not give warranties on galvanized products, which is why most homeowners go for Galvume instead. 
• Limited protection: Galvanized steel is protected from corrosion thanks to its zinc coating. However, this protection is limited. The zinc will wear off after a while and leave the steel exposed to corrosive elements. In addition, this metal is generally less protected from corrosive elements than some metals, like stainless steel.
• Visually unattractive: Not everyone finds this type of metal aesthetically appealing. The zinc coating gives the metal a dull look that some find unappealing. Also, the zinc coating starts to come off after some time, causing red rust, which isn’t an appealing sight.
• Not readily available: Galvanized steel roofing products are hard to come by in the market. This is because many manufacturers have hopped on the Galvalume train because it is more durable than galvanized steel, and property owners find it more beneficial. However, you will still find some areas in the US that use galvanized steel products more.
• Unsuitable for coastal environments: Steel’s zinc coating cannot withstand coastal environments and the conditions associated with them. When galvanized steel comes into contact with saltwater in the atmosphere, the zinc coating starts to break down, shortening its lifespan.

Conclusion

Several factors, including the type of coating used, the coating’s thickness, and the conditions you expose it to, influence the lifespan of galvanized steel. When you use and maintain galvanized steel properly, the coating will take longer to wear off, extending its lifespan and saving you some money.

However, you should also be aware that the choice of roofing contractor significantly impacts the success of your metal roof. When you use a professional who knows their onions, they can guide you on your choice of roofing material and give recommendations based on several factors, like your desire, environment, and budget.

Frequently Asked Questions

How much does galvanized metal roofing cost?

Galvanized metal roofing can cost between $4.50 and $17 per square foot or between $400 and $900 per square foot. 

Can galvanized steel rust?

Although it takes a long time for galvanized steel to rust, it eventually will. The zinc coating on the steel protects it from corrosive elements like water and oxygen. However, after a long time, the protective coating starts to wear off, and this is when rusting starts.

Can you paint galvanized steel?

Although hot dip galvanizing is cost-effective and sufficient to keep steel protected against corrosion for a long time, you can still paint your galvanized steel. There are several reasons why people would want to paint their galvanized steel. They include the addition of color for aesthetics and safety purposes, among others.  

How can you tell if a metal is galvanized?

One way to spot galvanized metal is to note its pattern. If you look at the metal and it has a spangle pattern, that means it is galvanized. A spangle pattern has the appearance of gray sponge-painted metal, with lighter and darker spots similar to those of a sponge-painted wall.

How long does galvanized steel last?

Hot-dip galvanized steel can last for as long as 50 years in normal environments. However, in corrosive environments, such as coastal ones, it has a life expectancy of about 25 years. The actual lifespan of galvanized steel depends on the environmental conditions. 

Contact us to discuss your requirements of Galvanized T-Steel. Our experienced sales team can help you identify the options that best suit your needs.

Galvanised steel is a popular choice in industrial, agricultural, and construction projects. The main purpose of galvanisation is to protect the steel from corrosion, and this is achieved by applying a thin layer of zinc, either through a process of ‘hot dip’ galvanising, electro-galvanising, or metal spraying.

There are a lot of reasons why you should choose galvanised steel for your engineering project. And there are a few more reasons why you shouldn’t. Now knowing what galvanised steel sheet properties are, we have highlighted the key benefits and drawbacks that will guide you to making the right choice for your project.

THE PROS OF USING GALVANISED STEEL SHEETS

Durability and longevity

TFM – or Time to First Maintenance – is calculated according to the appearance of rust on five percent of the galvanised steel sheet surface. What this means is that five percent of the zinc coating has now eroded, exposing the steel to corrosion. It is at this stage that maintenance needs to be implemented to protect the integrity of the steel and prolong its durability.

TFM varies according to the atmospheric conditions of the structure. For example, in a dry, rural area with little rainfall and pollution, a TFM could be over 100 years, while in a more humid tropical environment, that TFM might reduce to about 70 years.

By hot-dip galvanising a thin 6mm steel sheet, you are creating a zinc coating of 85 microns, which more than meets the corrosion performance required for many applications across the UK.

Smooth finish, rust-free, and lowered maintenance costs

A sheet of galvanised steel is smooth to the touch, making it easy to inspect. Being tough and durable, it is resistant to scratches and everyday damage. Any damage tends to occur through mishandling and untreated long-term wear and tear. Due to its smooth surface, should the galvanised steel sheet incur any damage, the integrity of the protection is compromised, making it prone to rusting. Fortunately, this makes it easily noticeable on regular inspection and therefore can be treated quickly and effectively. When it is damaged, it is the zinc that is in the first line of fire. That means that the steel underneath is protected and will only be affected if the blemish is left untreated.

Protection from contamination

The galvanisation process acts as a protective buffer against oxygen and moisture, resulting in a smooth, rust-free layer. As a result, the steel sheets are perfect for use in projects which require a clean, clinical environment, such as operating rooms and food preparation areas.

THE CONS OF USING GALVANISED STEEL SHEETS

Comparison of steel prices

Galvanised steel sheet prices may be prohibitive, particularly in large-scale projects. Compared with, for example, cold-rolled steel sheet, galvanised steel is considerably more expensive.

When pricing up a project, you need to consider its durability of the project. For a short-term project, which may be demolished in a short period of time, it would be more economical to use a less durable, but better-priced, alternative. However, for long-term structural projects, the additional costs will more than pay for themselves in terms of longevity and reduction in maintenance over the years. Cheaper is never normally better.

Beware of white rust

The galvanisation process ensures that the steel sheet remains resistant to rust. However, you need to be aware of the presence of white rust, which can develop over time if the steel is exposed to moisture and not maintained.

White rust is a white chalky substance that can form on the surface of zinc due to moisture. It can cause significant damage to the galvanised coating and can ultimately compromise the durability of the zinc coating.

Otherwise known as zinc hydroxide, this white rust must be treated immediately to prevent it from spreading and reversing the effect of the galvanisation process as a whole. But prevention is better than cure, so ensure the following steps are taken to minimise the risk of white rust in the first place.

• Make sure the galvanised steel sheets are packed in a dry, moisture-free environment.
• Ensure that there is good air circulation between sheets.
• Store the sheets at a slight angle to ensure that any water or moisture can be drained away and not sit stagnant on the surface of the steel sheets.
• Make sure the surface of the zinc coating is treated with a barrier or water repellent coating to minimise any contact between water and the galvanised surface of the steel sheet.

If your galvanised steel sheet has developed a white rust coating, then it can be treated. The treatment depends on the severity of the damage to date. If there is a light powdery residue, then it can usually be brushed off with no residual treatment required. However, the more established and severe the zinc oxidisation process, the more remedial treatment is required to ensure it does not compromise the long-term integrity of the galvanised coating.

There are more pros than cons to choosing galvanised steel sheets over alternatives for your construction and infrastructure projects. However, due care and attention need to be paid to the way the steel is stored, handled, and maintained if you are to get optimum return on your investment in the product.

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