CGI or Zinc Sheeting Specifications

Corrugated galvanized iron (CGI), also called Zinc Sheeting, is often used in secondary stages of emergency but in some cases may be needed in the acute stage as well.

Procurement location: Check national standards and local market conditions for local procurement. Deviations from the standards listed below should be approved by specialist.

Shipping and cost details: 20-50 sheets palletized


Coating Hot-dip zinc galvanized
Standard Wire Gauge (SWG) 26 minimum
Thickness .457mm/.018” minimum
Hardness 85 HRB minimum
Coating thickness 20 micrometers
Tensile strength 300N/mm minimum

Ensure that recipients have fasteners and support materials. Minimum nails needed:

High wind: 20 nails per square meter
Medium wind: 11 nails per square meter
Low wind 7 nails per square meter


Verify upon delivery:

  • Measure thickness of the coating with a “Coating thickness gauge”, which should cost approximately $150.
  • Measure the thickness of the CGI with a caliper or similar measuring tool.

Storage recommendations to prevent white rust:

  • Do not pile higher than 20-50 sheets (stacking 20-50 sheets with wooden layers in between, to allow for air, is fine as well)
  • Store the CGI inclined, so that condensation water can run off, or wrap tightly in plastic sheeting so condensation does not reach the CGI
  • Generally, do not store CGI for too long. Have a First-In-First-Out policy.

The hotter the climate, the more aggressive the corrosion.