Select a Steel Grade for Roofing

There are many factors governing the selection of the recommended grade of COLORBOND® steel to use. Atmospheric factors and the nature of the activity within the building are among the most important. Like steel roofing, the performance of steel walling can be influenced by a number of factors, including the environment. In the case of walling, the most important factor to be aware of is unwashed areas.

The table below serves as a guide for selection in marine environments.

ZINCALUME® steel and COLORBOND® steel are also suitable for light industrial environments however where the product is subject to heavy fallout, acid, alkali laden air or other corrosive chemicals please contact BlueScope Steel Direct on 1800 022 999 for advice on the recommended product and fasteners to use. This also applies to harsh service activities carried out within buildings such as intensive animal farming and indoor swimming pools.

Recommended BlueScope Steel Product Guide for Roofing in Marine Environments
Marine Environment Severity Distance From Breaking Surf Distance From Calm Marine Recommended Roofing Product
Very Severe Marine 0m-100m N/A SUPERDURA® Stainless steel
Severe Marine 100m-200m 0m-100m


COLORBOND® Ultra steel
Marine 201m-400m 101m-200m


Moderate 401m-1000m 201m-1000m


COLORBOND® steel, COLORBOND® Metallic steel or ZINCALUME® steel
Benign 1001m + 1001m + COLORBOND® steel, COLORBOND® Metallic steel or ZINCALUME® steel


  • Absolute performance is subject to local conditions (e.g. prevailing winds) and unwashed areas (i.e. regions of the roof not naturally washed by rain).
  • Above table applies to roofing product only.
  • The above table applies to salt marine influences only. For installations subject to severe, heavy industrial conditions, it is essential to consult a BlueScope Steel Sales Office for advice on the appropriate product. For further information, please see "Technical Bulletin 1A - Steel Roofing Products - Selection Guide" on our Technical Bulletins page.