Does Painting Corrugated Roofs Make Them Last Longer?

Businesses and residential properties alike have opted for corrugated metal roofs for decades, if not centuries, because they are affordable, low cost, have a unique aesthetic quality and can last an exceptionally long time if well maintained.

Since its invention in the 19th century, it has always been a popular building material, in no small part because of how strong and robust it is despite its relative lightness.

This is the result of the corrugation, but the long life of the material is typically thanks to the galvanised part of corrugated galvanised iron.

Galvanisation is where a coating of zinc is added to iron or steel to protect the sheet against rust and corrosion, something that can lead to many structural issues and require replacement sheets to be fitted.

This is useful, although if the coating scratches off it can lead to points of vulnerability with the corrugated metal.

However, one potential way around this is to do what a lot of businesses and homeowners already do and that is paint the corrugated sheets, at least the parts that are visible and exposed to the elements.

The reason for this is pretty much the same reason why galvanisation works. Corrosion is a form of oxidation; it happens when iron (including that in steel) comes into contact with water, the oxygen within it reacts to form iron oxide, which is the brown flaky rust that we associate with corrosion.

At a basic level, paint creates a barrier over the surface of the metal, not allowing the contact that is needed to create the reaction in the first place.

Galvanisation works in a similar way, although in practice it tends to slow the reaction rather than completely stop it.

Metal roofs should be painted for a variety of reasons including insulation and heat management, but it is also a cost-effective way to protect your roofing investment.