Can You Paint Galvanised Steel?

Before we discuss how to paint galvanised steel, let’s have a look at what it is and why it needs a specific approach when painting.

Galvanised steel is a type of steel that has been coated in a protective layer of zinc to prevent rust and corrosion. This process is known as galvanisation. It produces a steel surface that is resistant to moisture, which makes it a popular choice for outdoor and industrial use.

For more details, check out our article on the Differences Between Galvanised and Non-Galvanised Steel.

While galvanised steel gives excellent protection against rust, the zinc coating can be challenging when it comes to painting. This is because zinc is non-porous, which makes it difficult for standard paints to adhere to the surface. Without properly preparing the steel, paint can peel or flake off over time – which obviously isn’t ideal.

Also, galvanised steel often contains residual oils used during the galvanisation process. These oils can create a barrier between the paint and the surface, making adhesion even more difficult.

The good news is that with the right preparation, painting galvanised steel is entirely possible and can have excellent results.

Read on for a step-by-step guide on how to prepare and paint galvanised steel effectively:

1. Clean the surface thoroughly

Before you begin painting, the first step is to clean the surface of the galvanised steel thoroughly. This means removing any grease, oil or dirt that could stop the paint from adhering properly. You can use a mild soap and water, followed by rinsing with clean water. Make sure that the surface is completely dry before proceeding to the next step.

2. Use a primer

When painting galvanised steel, it’s important to use a suitable primer. Because the zinc coating is so smooth, the paint needs something to grip onto. Many primers are specifically designed to bond to metal surfaces like galvanised steel. This creates a surface that regular metal paint will bond onto. Apply the primer in thin, even coats and allow it to dry fully before applying any topcoat. Always follow the manufacturer's instructions on the tin too.

3. Choose the right paint

You’ll find that not all paints are suitable for galvanised steel. Look for products that are made particularly for use on metal or that are clearly compatible with galvanised surfaces. Acrylic-based or epoxy-based paints tend to work well.

Whatever paint you choose, make sure you apply it in light, even coats and give it time to dry between coats. Refer to the paint manufacturer’s instructions to ensure the paint has properly bonded to the surface.

Optional extra: Apply a topcoat – As galvanised steel is commonly used in outdoor projects, you might find that you need to apply a clear topcoat. This can provide extra protection against wear and tear, as well as UV exposure.

Painting galvanised steel can be useful in a variety of settings. Below are some common ways it can be used:

Outdoor fences and railings

While galvanised steel is already resistant to corrosion, painting can enhance its appeal and provide an extra layer of protection against the elements.

Industrial equipment

If galvanised steel is used in industrial settings, painting can help with a few things. For example, branding, identification or simply to match the equipment with the company’s colour scheme.

Home improvement projects

Painting galvanised steel is an excellent choice for DIY furniture projects, both indoors and outdoors. Not only does it offer durability, but you’ll also enjoy a sleek, polished finish.

Once you've painted your galvanised steel, regular maintenance is key to preserving its appearance. Follow the tips below to extend the lifespan of your painted surfaces:

Regular cleaning

Dirt and debris can collect on the surface, especially in outdoor settings. Clean the surface with mild detergent and water as regularly as needed.

Inspect for flaking or peeling

Over time, painted surfaces can experience wear and tear. If you notice any flaking or peeling, touch up the affected areas to prevent further damage.

Reapply topcoats as needed

Topcoats can be necessary due to weather exposure or high-traffic areas. In these instances, reapplying a clear topcoat will help maintain durability.