Will my Decra® roof rust?

It definitely will not. All Decra® products are made of a tried and tested material called ZM250; i.e zinc-magnesium protection with 250g of coating per sqm. ZM250 is a special steel coated with an alloy of 93.5 % zinc, 3.5 % aluminium and 3 % magnesium. The excellent corrosion resistance of ZM250 is attributable to the properties of the three components: on the surface of the cladding, aluminium and magnesium function as a barrier against corrosive substances and the zinc protects the steel via the “sacrificial effect”. Thanks to its 3% magnesium content, ZM250 steel offers self-healing on cut edges.