Building Supplies

Differences between Galvanised and Painted Steel

A common question we are asked in our retail store is to explain the difference between galvanised steel and painted steel, helping our customers decide which is the best option for their needs.

In this article we will compare these two, explain what each one is, then outlining the pros and cons for each of these.

What is galvanised steel?

Galvanised steel is simply steel that has been given a coating of zinc, which helps protect the steel from corrosion.

The actual galvanisation process involves:

  • Cleaning the steel
  • Creating a molten zinc solution that is heated to about 450 degrees
  • Dipping the steel in this molten zinc solution
  • This produces a chemical reaction that results in a substance called zinc carbonate

Upon dipping, the zinc will bond to the steel, hardening out of the solution. This coating protects the steel layer underneath from moisture and elements such as salts, preventing corrosion while also increasing the strength of the steel.

What is painted steel?

As the name suggests, painted steel is exactly that: a layer of paint is applied to steel, creating a protective layer from the elements.

The process of applying paint to steel involves:

  • Cleaning the steel using a technique called sandblasting
  • This also roughens up the surface, allowing the paint to bond better
  • Spray the paint

What are the differences between galvanised and painted steel?

Galvanised SteelPainted Steel
Thickness is consistent across one piece of steelCoating thickness can vary across one piece of steel
Durable coating, hard to scratchLess durable coating, easy to scratch
 Paint is a barrier protection only – scratches expose the steel underneath
More expensive than using paintCheaper than galvanising
Due to the greater hardness of galvanisation, it is more corrosion resistant and requires less maintenance over timeAn enamel coat can be applied over the paint for extra strength and durability
You can have any colour as long as it is silverColour choices are infinite
Naturally lasts for many years, around 50 yearsAfter 3-5 years the paint wears down, and at the 5-7 year mark a recoat of paint will be required

What does The Haggarty Group recommend?

As you can see in the table above, both have negatives and advantages.

If you are after a lower cost option with colour choices, paint coatings are quite effective. Having said this, there are several situations that will better suit galvanised steel, such as:

  • Do you live near the coast? If yes, then we are sure you know that salty air is the enemy of steel. For this reason, galvanised steel is a much sturdier option.
  • Are you using the steel as part of a livestock shelter? If yes, then be aware that waste from animals can be corrosive, and for such applications galvanised steel is a preferred option.
  • Lastly, if you need to frequently wash the steel (for example if its part of your shed), of if it is regularly exposed to water, then galvanised steel will give you more longevity.

How can we help you?

At The Haggarty Group, we have the knowledge and experience to help you with any of your steel-related projects. Come in store for a chat, or give us a call today.