Galvanised steel profiled metal roofing – white rust

Causes

The zinc coating has corroded when water is trapped between sheets at laps and joints. This may occur during roofing installation or during storage before installation

Insufficient rain washing. Rain washing tends to be less effective on roofs with less than 15 degrees slope

Listed under: metal, steel, Roof, cladding, durability, corrosion, rust, roof cladding, profiled metal

Cause

The zinc coating has corroded when water is trapped between sheets at laps and joints. This may occur during roofing installation or during storage before installation

Repair

  • brush to remove the deposits with a stiff bristle brush – do not use a wire brush. Paint brushed areas with a zinc-rich primer and a metal primer, then apply at least two coats of acrylic paint 

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Cause

Insufficient rain washing. Rain washing tends to be less effective on roofs with less than 15 degrees slope

Repair

  • brush to remove the deposits with a stiff bristle brush – do not use a wire brush. Paint brushed areas with a zinc-rich primer and a metal primer, then apply at least two coats of acrylic paint 

Back to top