Metal roofs are popular with Australian business owners because they are durable and last a long time, but it's important to consider how to make your roof last as long as possible. Exposure to the elements will, over time, lead to the degradation of any metal roof, but a protective coating is a simple way to avoid any issues. Learn more about the reasons why you should apply a protective coating to your metal roof, and find out about the options available to you.

Reasons to apply a protective coating

Manufacturers normally add a protective coating to any metal roofs they produce. A factory finish may include galvanisation (a protective layer of zinc sulphate) and/or a special layer of paint, but this type of protection won't last forever.

A protective coating offers several benefits. These include the following:

• Protection against rust. As the original layer wears off, the steel underneath becomes susceptible to corrosion.
• A barrier against water leaks. Metal roofs expand and contract as the temperature changes, which can allow moisture to get in.
• Improved aesthetics. A protective coating can make the roof look smarter and fresher, which is perfect for new business owners who don't want to spend a lot of money on a renovation project.
• Improved energy efficiency. A protective coating could cut the surface temperature of a metal roof by up to 40 percent, helping you to keep the building cooler for your workers in the heat of summer.

By extending the life of your metal roof with a protective coating, you will also save money and prevent waste. Old metal roofs ultimately end up in landfill sites, when something as simple as a new protective layer could avoid this wastage.

Of course, a protective coating is not the answer to every problem. If a roof is in a poor state of repair, renovation may no longer be a solution. In this case, you may simply need to replace the roof.

Choosing the right protective coating

It's important to choose the right type of protective coating for your metal roof. Acrylic roof coatings are suitable for most metal roofs (and some spray foam roofs, too). This spray-on product gives you a seamless, acrylic membrane that normally includes fungicides and products to stop mildew forming. The material is easy to use and dries quickly, so you don't normally need to cover the roof after application, provided you work on a sunny day, with minimal disruption to your business activities. Other specialist aluminium coatings include asphalt and other mineral fibres to create a hard-wearing surface that dramatically cuts the roof's temperature.

Whichever product you choose, follow the manufacturer's instructions carefully. You will need to clean and prepare the surface of the roof for the protective coating, and you may also need to apply a primer.

Protective coating application methods

The good news is that nearly every type of metal roof is a good candidate for a protective coating. The size and shape of the roof seldom make any difference to the coating, but, of course, the building design will influence the method you use to apply the coating. While you can apply a coating with a roller or a spray gun, the latter is normally the best option.

Airless spray guns are generally the best way to apply a new protective coating because they are quick and easy to use. The irregular surface and awkward design of some metal roofs makes it difficult to use a roller in many situations, and an airless spray gun is less likely to lead to roof damage. If you use a roller, you may need to walk on the roof, which could lead to unwanted dents and scratches.

When to apply

The time a protective coating will last varies according to several factors. The size of the building, its location and the way people use the building can all put more or less pressure on a metal roof. In turn, these factors can all accelerate the life of a protective coating. A high-quality coating will also need less frequent replacements.

Most protective coatings come with a warranty against water leaks. It's generally a good idea to replace or renew these coatings before the warranty expires, as this will guarantee continuity of protection.

A protective coating could dramatically extend the life of your metal roof. Talk to a supplier in your area, such as Cormac Contracting Pty Ltd, for more information and advice.