Select a Steel Grade for Walling

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.

Unwashed Areas

Since walls are vertical surfaces, they can be sheltered from general rain washing, particularly towards the top of the wall, adjacent to overhanging eaves. In these regions, dust and dirt which would otherwise be washed away by rain, tends to build up. This leads to an increase in the time that the material surface is in contact with sufficient moisture to cause corrosion. When the build-up of dust and dirt includes marine salts, and/or other pollutants, unwashed area corrosion is further exacerbated.


Modern building design often incorporates large overhanging eaves, verandahs and walkways in combination with walling made from COLORBOND® prepainted steel. The designer should understand the responsibility inherent in the inclusion of such areas, and either minimise their extent, select the appropriate COLORBOND® steel product for the application or incorporate a stringent regular maintenance routine after construction.

Product Selection & Maintenance

The corrosion effects observed in unwashed areas can be minimised by regular washing with fresh clean water. The following table gives an indication of the required maintenance period, plus serves as a guide for selection of an appropriate walling product.

Recommended BlueScope Steel Product Guide for Walling
Marine Environment Severity Distance From Breaking Surf Distance From Calm Water Recommended Walling Product Minimum Maintenance Interval
Very Severe Marine 0m-100m N/A COLORBOND® Stainless steel 6 months
Severe Marine 101m-200m 0m-100m


COLORBOND® Stainless steel 6 months
Marine 201m-400m 101m-500m COLORBOND® Stainless steel 6 months
COLORBOND® Ultra steel 3 months
Moderate 401m-1000m 501m-1000m


COLORBOND® Ultra steel 6 months
Benign 1001m + 1001m + COLORBOND® steel
6 months

* Note: This is a guide only. For more information, see Technical Bulletin TB 01B - Steel Walling Products - Selection Guide (Oct 2013, 159 KB) on our Technical Bulletins page. Due to the wide variation in the severity of particular environments, customers should contact BlueScope Steel Direct on 1800 022 999 for assistance in interpretation of the particular locale.