If your metal roof is up for replacement, you need to choose a material that's right for your local climate and home architecture. Especially popular in Australia, steel in one metal that is available in several varieties. Here's an explanation of the types of steel that endure on roofs right across Australia.
How Chromium Helps Stainless Steel
Forming the backbone of many highrises and bridges, steel is an incredibly durable material. Standard varieties, however, are susceptible to rust. One type that resists corrosion is stainless steel, making it ideal roofing material. The reason for this immunity is the chromium content within. All steels combine iron and carbon with other substances. Once the steel contains ten to thirty per cent chromium, which naturally repels rust, it becomes stainless steel. Roofs made of stainless steel are particularly suited to coastal regions that experience corrosive salty air and moisture.
The Protective Power Of Zinc: Galvanised Steel
Another type of roofing you might come across is galvanised steel. Rather than including chromium within, these roofing sheets feature a protective layer of zinc. This coating creates a barrier that protects the inner metal from moisture and air to prevent corrosion. The manufacturing process involves submerging the metal into a hot bath of molten zinc.
Aluminium, Zinc And Silicon
While galvanised steel has an outer zinc layer, other products (such as Zincalume) have a coating of aluminium, zinc and small amounts of silicon combined for added protection. Aluminium is notoriously rust-resistant, so including this within the protective layer enhances the benefits.
Plus Painted Polyester
Other kinds of steel (Colorbond) come with protective coatings, plus a layer of polyester paint to produce exceptionally durable and long-lasting metal. Different grades of this type of roofing suit various air environments. Beachside homes, for example, need to withstand caustic salty coastal air, so choosing the appropriate grade will improve how your roof fares.
Energy-Efficient Steel
Once technology does its work, steel roofs can oppose rust for long periods. However, another quality of steel is that it changes temperature quickly in line with the surrounding air, rather than holding onto heat or cold. This can prove inefficient in terms of energy use.
Dealing with this, specialised technologies and coatings can reduce the heat that radiates through a roof from the sun, helping to keep the rooms underneath cooler. During winter, insulated versions can help to hold heat inside also. Steel roofs, though, are particularly ideal for hot, humid climates because they cool rapidly once the sun sets, which allows refreshing night breezes to cool the building underneath. If you're having a metal roofing reroof, your contractor can advise on the best metal for your structure and climate.
