Does Galvanized Steel Rust?
Many people who live or work in corrosive environments worry that their metal fences will corrode. Many even ask the question, “does galvanized steel rust.”
If you’re looking for a durable metal fence for your home or property and you’re wondering does galvanized steel rust, you’re in the right place. Here’s what you need to know.
What Is Galvanizing?
Galvanizing is a process that deposits a layer of zinc on the surface of steel posts, fence panels, gates and so on. There are several ways to do this, but the most common are hot dip galvanizing – where steel items are dipped in a bath of molten zinc – and electro galvanizing, which uses electrical current to create a layer of zinc on the metal.
How Does Galvanizing Protect Metal?
Galvanizing protects steel in a number of ways.
As you probably know, steel has a high iron content. In other words, it is a ferrous metal.
Ferrous metals (and iron, in particular) oxidizes when exposed to oxygen. Some common chemicals like salt accelerate this process, resulting in what we know as rust.
The zinc layer created on galvanized steel creates a physical barrier between the steel, the air and things like salt. It also acts as a “sacrificial layer.” This means that even if the galvanizing is scratched or damaged, any remaining zinc will act to protect the underlying steel.
How Long Does Galvanized Steel Last?
The next question many people ask when investigating does galvanized steel rust is how long galvanized metal products can be expected to last.
The answer is it depends on where they are installed and what the environment is like.
Galvanized steel in inland areas, far from marine air and outside of industrial zones, could last forty or fifty years or more.
The same galvanized fence installed right next to the ocean could show signs of rust in a matter of months.
It’s always best to consider where your fence will be installed before you decide what kind of metal and coating will be best for the project. There’s some great information on the American Galvanizers Association website.
How to Slow Down Rusting of Galvanized Steel
The good news is that there are several things you can do to slow down any potential rusting of galvanized steel and to extend the life of your galvanized steel fence as long as possible.
The most important one is to prevent mechanical damage to the zinc layer on the fence. Cuts, scratches, and dents in the steel will weaken the zinc layer, allowing water to penetrate below, reaching the steel and starting the process of oxidization and rust.
Another big factor is the quality of the coating you have. This applies both to the thickness of the zinc, and the quality of the application. Always choose galvanized steel fence products from reputable manufacturers who provide mill certificates and warranties on their galvanized steel, and if you have to have steel hot dip galvanized, choose a reputable service provider who delivers quality results.
The last thing you need to know about slowing down rusting on a galvanized steel fence is that you want to avoid any on-site modifications if you can, and when you can’t, you need to treat all cuts, welds, and modifications with a high-quality cold galvanizing product.
Alternatives to Galvanized Steel
If you have to install a fence in a highly corrosive environment, like next to the ocean, you might want to consider alternatives to galvanized steel.
You can get various fence systems in grade 304 and 316 stainless steel or in fence-grade aluminum alloys, both of which are metal fence options that will be much less prone to rusting and corrosion. Even these types of fences aren’t completely immune to chemicals and salt damage, but they last longer than galvanized products.
If you don’t need a metal fence, there are several other options like composite fence, vinyl fence, wood fence or precast concrete fence that will be more corrosion resistant even in marine and industrial environments.
Duplex Coating for Fences
If you decide to install a galvanized steel fence, you can extend the fence's lifespan by opting for a duplex-coated fence system.
This is a fence that is either painted or powder coated after galvanizing, adding another layer of physical protection to the galvanized metal below.
Always Share the Location of Your Site
The best thing you can do when you’re planning a fence and wondering does galvanized metal rust and will it be a factor for your project is to tell fence companies where your site is.
This will help them to determine what kind of environmental factors might be at play, and that means you get a fence that will have a longer corrosion-free lifespan.
