Rusting flashings and metal components

Cause

Air-borne salt, dust or dirt accumulating under flashings and metal components

Repair

  • remove corrosion by brushing with a stiff bristle brush; prime sanded/brushed areas with a zinc-rich primer and a metal primer, particularly where the flashing is lapped; apply at least two coats of acrylic paint
  • if corrosion is severe, replace existing flashings with copper or factory-coated steel flashings, ensuring that copper (where used) is compatible with adjacent building materials 

Cause

Zinc (galvanizing) or aluminium/zinc or zinc/aluminiuim alloy coating has been scratched or eroded, exposing steel

Repair

  • remove corrosion by brushing with a stiff bristle brush; prime sanded/brushed areas with a zinc-rich primer and a metal primer, particularly where the flashing is lapped; apply at least two coats of acrylic paint
  • if corrosion is severe, replace existing flashings with copper or factory-coated steel flashings, ensuring that copper (where used) is compatible with adjacent building materials 

Cause

Acidic leachate from cedar or H4-treated timber (containing copper-based preservatives)

Repair

  • remove corrosion by brushing with a stiff bristle brush; prime sanded/brushed areas with a zinc-rich primer and a metal primer, particularly where the flashing is lapped; apply at least two coats of acrylic paint
  • if corrosion is severe, replace existing flashings with copper or factory-coated steel flashings, ensuring that copper (where used) is compatible with adjacent building materials