ZM Coatings

ZM coatings are zinc-aluminium alloy coatings with a majority of zinc and a small amount of magnesium. Steel with a continuously hot-dipped coating of zinc with 5 -13% aluminium and 2 - 4% magnesium is designated in AS 1397:2011 as ZM. In New Zealand, it is commonly marketed as ZAM.

The coating weights are similar to Zinc coatings, with ZM 240 used for products which will later be coil coated and ZM 450 for unpainted products.

Unpainted ZM products have been used for roofing accessory and rainwater cladding applications in New Zealand, but are more commonly found in factory pre-painted products.