An urgent reminder on the importance of compliant zinc-coated tophats

Hebel wall panels have a warranted lifespan of 20 years and continued performance beyond. To ensure the warranty and compliance of Hebel wall panels that are directly connected to structural framing, those framing components must meet specific durability standards. Steel top-hats form an integral part of the structural framing in an external wall system.

The NASH Steel Framing Standard, and AS1397, specifies that steel frame components must have a minimum protection coating of Z275. This requirement is crucial in ensuring a steel framing system will meet the relevant corrosion category requirements for its intended lifespan. In low-rise wall installations with face-sealed systems, the internal wall cavity falls under a C2 corrosion category, necessitating a Z275 (zinc) or alternatively an AZ150 (aluminium zinc) coating protection.

Our project inspection teams have noted that some installers have been substituting Hebel top hats with other brands, including imported top-hats that are visual copies of genuine CSR Hebel top-hats. Samples received from the market have been tested independently, with several substitute top-hats demonstrating zinc coatings as low as Z100 – significantly lower than the minimum Z275 required.

It is critical to note that any steel framing element not meeting this Z275/AZ150 requirement would be deemed non-compliant, under Australian Standards, and our Hebel Codemarks. This discrepancy would lead to reduced durability and increases the risk of costly rework when the building certifier challenges the substitution and requests evidence of corrosion resistance. 

CSR Hebel top-hats are quality Australian made by Rondo. CSR guarantees the zinc coating standard of Z275/AZ150 in our top-hats and metal angles, and this value helps to ensure system compliance.