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Galvanized verus AZ (Aluminium-Zinc) Roof Sheeting

Galvanized or AZ roof sheeting – which to choose?

We are used to seeing and hearing the term galvanized roof sheeting for many years now. This has been the material traditionally used on our roofs. Galvanized steel is coated with almost 100% zinc and while this does slow down rusting it will occur quicker where material is exposed to moisture from the sea, dirt or grim.

Innovative methods and production techniques are taking steel to new levels of durability and service life. AZ coated roof sheeting is one such innovation. The material is the ideal solution for your roof especially in coastal regions. AZ roofing material is coated with 55% aluminium, 43.5% Zinc and 1.5% Silicon also referred to as 55% Aluminium-Zinc coating technology.

What is the performance difference between the two materials? Galvanizing is sacrificial in nature. This means that it corrodes preferentially to steel, but it sacrifices itself (the coating) to the effects of corrosion. Over time the barrier will be gradually be consumed until the coating no longer remains, exposing the steel. An AZ coating provides an inherent protective barrier compared to zinc, which prevents the spread of corrosion. As a result AZ combines the benefit of preferential corrosion (zinc), while slowing its spread (aluminum). This offers not only longer protection overall but slows corrosion that is caused by scratches or cuts to the surface. The mix of the two materials was extensively developed in the 1960s and 70s to provide an optimized mix for long-term performance.
Below is a typical example of how AZ material performs in comparison to galvanized material.

For long lasting roof cover consider using roof sheeting with AZ coating. You will have peace of mind for many years to come.